Quant Memo
Editorial
The Quant Memo editorial byline for explainers, paper summaries, and reference pieces produced for the platform.
Writing by Quant Memo
Getting Expected Shortfall Right: Acerbi and Tasche on the Definition That Actually Works
Paper ExplainedEveryone agreed the average loss in the tail was the better risk measure. It turned out there were several ways to define it, and only one of them is genuinely coherent.
Jul 13, 2026
How Complicated Should Your Model Be? Akaike's Answer
Paper ExplainedA bigger model always fits your data better. Akaike found the exact price you should charge for each extra parameter, and turned model selection from an art into arithmetic.
Jul 13, 2026
Any Shape of Order Book: Alfonsi, Fruth and Schied on Optimal Execution
Paper ExplainedEarlier execution models assumed the order book was a flat block of liquidity. Real books are lumpy. This paper solved the problem for a book of any shape at all.
Jul 13, 2026
Measuring Impact With Real Orders: Almgren, Thum, Hauptmann and Li
Paper ExplainedEveryone theorised about market impact. This team took roughly 700,000 real institutional orders and just measured it, producing the model brokers still quote today.
Jul 13, 2026
Five Ratios and a Verdict: Altman's Z-Score
Paper ExplainedAltman took five ordinary accounting ratios, weighted them into a single number, and produced the first statistical model that could tell you which companies were about to go bust.
Jul 13, 2026
One Ratio to Measure Liquidity: Amihud's ILLIQ
Paper ExplainedAmihud built a liquidity measure out of nothing but daily returns and volume, and showed that illiquid stocks earn more, and that the whole market repriced when liquidity dried up.
Jul 13, 2026
Illiquid Stocks Must Pay You More: Amihud and Mendelson's Liquidity Premium
Paper ExplainedIf a stock is expensive to trade, nobody will hold it unless it is cheap enough to compensate. Amihud and Mendelson turned that obvious thought into an asset pricing theory.
Jul 13, 2026
The Volatility Models Were Fine, the Scorecard Was Broken
Paper ExplainedFor years GARCH looked useless because it 'explained' only about five percent of tomorrow's volatility. Andersen and Bollerslev showed the models were right and the grading was wrong.
Jul 13, 2026
How Far Back Should You Look? Andrews and the Bandwidth Problem
Paper ExplainedNewey-West standard errors require you to pick a lag length, and everyone was picking one arbitrarily. Andrews worked out what the optimal choice actually is and how to let the data make it.
Jul 13, 2026
The Riskiest Stocks Paid the Least: the Volatility Puzzle
Paper ExplainedAng, Hodrick, Xing and Zhang found that the stocks bouncing around the most for their own private reasons went on to earn the worst returns of all. Theory says this should not happen.
Jul 13, 2026
Letting the Economy Into the Yield Curve: Ang and Piazzesi
Paper ExplainedBond models ignored inflation and growth. Macro models ignored arbitrage. Ang and Piazzesi built the first serious bridge, and forecasts got better.
Jul 13, 2026
Getting Paid for Fear: the ARCH-M Model
Paper ExplainedEngle, Lilien and Robins let the volatility forecast feed straight back into the expected return, turning 'risk should be rewarded' from a slogan into something you can actually estimate.
Jul 13, 2026
Four Rules Every Risk Number Should Obey: Artzner and the Birth of Coherent Risk
Paper ExplainedInstead of proposing a new risk measure, Artzner and coauthors asked what any sane risk measure must do. Then they showed that Value-at-Risk, the industry standard, breaks one of the rules.
Jul 13, 2026
The Devil in the Details: How You Build a Factor Changes What It Is
Paper ExplainedAsness and Frazzini showed that the standard academic value factor uses a stock price that is up to eighteen months stale, and fixing that one detail changes everything.
Jul 13, 2026
Why Risk Parity Works: Leverage Aversion, Explained
Paper ExplainedRisk parity holds a lot of bonds and levers them up. That sounds like a gimmick. Asness, Frazzini and Pedersen explain why it is actually harvesting a premium other investors cannot reach.
Jul 13, 2026
Good Companies at Fair Prices: Quality Minus Junk
Paper ExplainedIf a company is safe, profitable and growing, investors should pay up for it. Asness, Frazzini and Pedersen found they don't pay up nearly enough, and that gap is a factor.
Jul 13, 2026
Pairs Trading, Industrialised: Avellaneda and Lee's Statistical Arbitrage
Paper ExplainedInstead of matching stocks two at a time, Avellaneda and Lee stripped out every common factor from every stock at once and traded whatever wiggle was left over.
Jul 13, 2026
The Whole Life of an Order: Bacry, Iuga, Lasnier and Lehalle on Impact at Every Scale
Paper ExplainedMost impact studies measure one moment. This one followed 400,000 real orders from the first trade to the final settling of the price, and found the market never saw them coming.
Jul 13, 2026
How Many Times Did the World Change? Bai and Perron
Paper ExplainedReal relationships do not break once. Bai and Perron built the machinery to find several unknown regime changes at once, and to test how many there really are.
Jul 13, 2026
Why Nobody Fixes the Low-Volatility Anomaly
Paper ExplainedBoring stocks beat exciting ones, and professional investors are the very people least able to do anything about it, because they are all measured against a benchmark.
Jul 13, 2026
Stocks as Lottery Tickets: the MAX Effect
Paper ExplainedBali, Cakici and Whitelaw found that a stock's single best day in the past month predicts terrible returns going forward. Investors pay up for the dream of a jackpot.
Jul 13, 2026
Long-Run Risk: The Faint Signal Buried in Economic Growth That Terrifies Investors
Paper ExplainedBansal and Yaron argued that what scares investors is not this year's recession but a tiny, nearly invisible drift in the long-term growth rate, and that a small permanent change in the future is far more frightening than a big temporary one.
Jul 13, 2026
The First Crack in the CAPM: the Size Effect
Paper ExplainedIn 1981 Rolf Banz noticed that small companies had beaten large ones by more than their risk could explain. It was the first big anomaly, and it opened the door to everything that followed.
Jul 13, 2026
All That Glitters: Why Retail Investors Buy Whatever Is in the News
Paper ExplainedBarber and Odean showed individual investors buy the stocks that grab their attention, because they can only sell what they already own, but they can buy anything.
Jul 13, 2026
Boys Will Be Boys: Overconfidence, Gender, and the Cost of Trading
Paper ExplainedIf overconfidence causes excessive trading, then the group psychology says is more overconfident should trade more and lose more. Barber and Odean found exactly that.
Jul 13, 2026
Trading Is Hazardous to Your Wealth
Paper ExplainedBarber and Odean tracked 66,465 households and found the ones who traded the most badly lagged the market, while the ones who did almost nothing nearly matched it.
Jul 13, 2026
Two Biases, One Model: Barberis, Shleifer and Vishny on Investor Sentiment
Paper ExplainedHow can markets underreact to news at short horizons and overreact at long ones? BSV built a single investor who does both, using two well-documented psychological biases.
Jul 13, 2026
How Wrong Is Your Volatility Number? Barndorff-Nielsen and Shephard Answer
Paper ExplainedRealized volatility gave everyone a way to measure market jumpiness. This paper gave them the error bars, which turns out to matter enormously.
Jul 13, 2026
Managing to a VaR Limit Can Make Your Losses Worse: Basak and Shapiro
Paper ExplainedGive a trader a Value-at-Risk limit and watch what they optimize. Basak and Shapiro show they will take more risk, not less, and lose more when they lose.
Jul 13, 2026
Cheap Stocks Won, and Everyone Ignored It for Fifteen Years
Paper ExplainedSanjoy Basu showed in 1977 that stocks with low price-to-earnings ratios beat expensive ones on a risk-adjusted basis. It was the value effect, found sixteen years before Fama and French made it famous.
Jul 13, 2026
Both, Actually: Bates Combines Jumps and Stochastic Volatility
Paper ExplainedBates tested whether random volatility alone could explain option prices, found that it could not, and showed you need jumps as well.
Jul 13, 2026
Check Your Portfolio Less: Myopic Loss Aversion
Paper ExplainedBenartzi and Thaler explained why stocks pay so much more than bonds: investors hate losses and look at their portfolios far too often, so they see far too many losses.
Jul 13, 2026
Accept Some Mistakes: Benjamini and Hochberg's False Discovery Rate
Paper ExplainedWhen you run thousands of tests, demanding zero false positives is too strict to find anything. This paper proposed a smarter goal: control the fraction of your discoveries that are wrong.
Jul 13, 2026
Where VWAP Came From: Berkowitz, Logue and Noser Measure the Real Cost of Trading
Paper ExplainedThe most widely used benchmark in institutional trading was invented in a 1988 paper trying to answer a simple question: how much does it actually cost a big fund to trade?
Jul 13, 2026
The Market Takes Months to Read an Earnings Report
Paper ExplainedGood earnings surprises keep pushing a stock up for months after the announcement. Bernard and Thomas showed this is not hidden risk, it is investors failing to do simple arithmetic.
Jul 13, 2026
The First Real Answer to How Fast Should I Trade: Bertsimas and Lo
Paper ExplainedIf you have to sell a million shares by Friday, when do you sell them? Bertsimas and Lo turned that vague worry into a solvable maths problem and got a surprisingly boring answer.
Jul 13, 2026
Nudge One Number, Rebuild the Whole Portfolio: Best and Grauer on Optimizer Fragility
Paper ExplainedBest and Grauer worked out exactly how violently a mean-variance portfolio reacts to a small change in one expected return. The answer explains why nobody trusts optimizers.
Jul 13, 2026
The Map of the Field: Biais, Glosten and Spatt's Microstructure Survey
Paper ExplainedThree of the field's architects sat down and drew the whole map of market microstructure, from why spreads exist to how markets should be designed.
Jul 13, 2026
Why Sensible People Stampede: Informational Cascades
Paper ExplainedBikhchandani, Hirshleifer and Welch showed that perfectly rational people watching each other will all end up copying, and the whole crowd can be wrong because of two early coin flips.
Jul 13, 2026
Separating the Shudder from the Shock: Bipower Variation
Paper ExplainedRealized volatility mixes together the market's ordinary churn and its sudden violent jumps. Barndorff-Nielsen and Shephard found a way to measure the churn alone, and subtract to reveal the jumps.
Jul 13, 2026
Forget the Spot Price: Black's Formula for Options on Futures
Paper ExplainedBlack realised that if you price an option off the forward instead of the spot, storage costs, dividends and convenience yields all vanish from the problem.
Jul 13, 2026
The Trip Wire: Black and Cox Let Companies Default Early
Paper ExplainedMerton let a company fail only on the day its debt came due. Black and Cox added the trip wire that lets creditors pull the plug the moment the firm crosses a line.
Jul 13, 2026
The Tree That Goldman Built: Black, Derman and Toy
Paper ExplainedA one-factor interest rate model that lives entirely on a binomial tree, keeps rates positive, and fits both today's yields and today's volatilities. It ran real trading books before it was ever published.
Jul 13, 2026
Putting the CAPM on Trial: Black, Jensen and Scholes Test the Theory
Paper ExplainedThree future legends built the first serious empirical test of the CAPM, invented the portfolio-sorting method every quant still uses, and found that the model's central line was real but bent in a way theory could not explain.
Jul 13, 2026
Unchaining the Knobs: Black and Karasinski's Lognormal Short Rate
Paper ExplainedBlack-Derman-Toy accidentally tied mean reversion to volatility. Black and Karasinski cut the wire, giving traders three independent dials and a rate that stays positive.
Jul 13, 2026
In Praise of Dumb Money: Fischer Black's 'Noise'
Paper ExplainedBlack argued that people trading on nothing at all are what make markets possible, and that prices are usually somewhere in the right neighborhood rather than exactly right.
Jul 13, 2026
What Happens to the CAPM When You Cannot Borrow Freely: Black's Zero-Beta Model
Paper ExplainedFischer Black noticed that the CAPM's flattest, most stubborn empirical failure disappears once you admit that most investors cannot borrow at the Treasury rate, and the fix he proposed is the intellectual root of low-volatility investing.
Jul 13, 2026
Fear Predicts Returns: Bollerslev, Tauchen and Zhou
Paper ExplainedWhen the gap between what options charge for volatility and what volatility actually delivers gets wide, the stock market tends to go up. It beats the price-earnings ratio at forecasting returns.
Jul 13, 2026
Why Prices Look Random When Order Flow Obviously Is Not
Paper ExplainedOrder flow is one of the most predictable things in finance. Prices are almost perfectly unpredictable. Bouchaud and colleagues explained how both can be true at once.
Jul 13, 2026
Just Roll the Dice: Boyle Brings Monte Carlo to Option Pricing
Paper ExplainedBoyle's insight was almost embarrassingly simple: if an option's price is an average over possible futures, simulate a lot of futures and take the average.
Jul 13, 2026
Making the Model Speak the Market's Language: the LIBOR Market Model
Paper ExplainedTraders had been pricing caps with a formula that no model justified. Brace, Gatarek and Musiela built the model that made the market's own formula correct.
Jul 13, 2026
Consumption Beta: Breeden's One-Factor Model That Should Have Replaced the CAPM
Paper ExplainedBreeden showed that all of Merton's many risk factors collapse into a single one, how an asset moves with what people actually eat, giving finance a model that is both simpler and better grounded. Then the data refused to cooperate.
Jul 13, 2026
Reading the Market's Mind: Breeden and Litzenberger Extract Probabilities From Option Prices
Paper ExplainedBreeden and Litzenberger showed that the whole probability distribution the market believes in is sitting inside the option chain, if you know how to look.
Jul 13, 2026
Random Forests: Why a Crowd of Deliberately Weakened Trees Beats One Smart One
Paper ExplainedBreiman's insight: build hundreds of decision trees, cripple each one on purpose so they disagree, then average them. The result is one of the most reliable predictors ever invented.
Jul 13, 2026
The Two Cultures: Breiman's Attack on the Way Statistics Was Done
Paper ExplainedDo you want a model that explains, or a model that predicts? Breiman argued the statistics profession had spent decades choosing wrong, and finance is still arguing about it.
Jul 13, 2026
The 93.6 Percent Number That Everyone Misquotes: Brinson, Hood and Beebower
Paper ExplainedThe most cited statistic in asset allocation says policy explains 93.6 percent of performance. It is a real result. It does not mean what almost everyone thinks it means.
Jul 13, 2026
The Volatility Forecast That Needs No Model: Britten-Jones and Neuberger
Paper ExplainedImplied volatility used to mean 'the number you get by inverting Black-Scholes', which is awkward when Black-Scholes is wrong. This paper extracted the market's volatility forecast without any model at all, and the VIX was rebuilt around it.
Jul 13, 2026
Squeezing the Answer From Both Sides: Broadie and Glasserman on American Options
Paper ExplainedSimulation runs forwards, early exercise reasons backwards. Broadie and Glasserman's fix was to build two deliberately biased estimators, one too high and one too low, and trap the truth between them.
Jul 13, 2026
Do Fast Traders Help Prices Find the Truth? Brogaard, Hendershott and Riordan
Paper ExplainedWith data identifying which trades came from high frequency firms, the authors could finally ask whether the fast traders push prices toward fair value or away from it.
Jul 13, 2026
The Wolves Smell Blood: Brunnermeier and Pedersen on Predatory Trading
Paper ExplainedIf the market knows you have to sell, the other traders will not help you. They will sell first, buy back cheap, and profit from your distress.
Jul 13, 2026
The Speed Race Is a Design Flaw: Budish, Cramton and Shim on Frequent Batch Auctions
Paper ExplainedThe high frequency arms race is not greed, it is a bug in how markets process time. Fix the clock and the race has nothing to run for.
Jul 13, 2026
By Force of Habit: Why Risk Feels Terrifying in a Recession
Paper ExplainedCampbell and Cochrane solved the equity premium puzzle with one human observation: your fear of losing money depends not on how rich you are, but on how close you are to the standard of living you have gotten used to.
Jul 13, 2026
Campbell and Shiller: Why a High Price Must Mean Bad News Somewhere
Paper ExplainedCampbell and Shiller turned a piece of accounting into an inescapable trap: if the market looks expensive, then either dividends must grow fast or future returns must be low, and there is no third option.
Jul 13, 2026
The Curve Predicts, but Backwards: Campbell and Shiller's Puzzle
Paper ExplainedThe expectations hypothesis says a steep curve means long yields will rise. Campbell and Shiller found long yields tend to fall instead. The sign is wrong, and it gets more wrong the longer the bond.
Jul 13, 2026
Pricing a Thousand Options at Once: Carr and Madan's Fourier Transform
Paper ExplainedCarr and Madan borrowed a signal-processing algorithm and made it price a whole strip of options in one shot, turning exotic models from academic curiosities into production tools.
Jul 13, 2026
Why Insurance Is Always Overpriced: Carr and Wu on Variance Risk Premiums
Paper ExplainedThe market charges more for volatility than volatility ends up costing. Carr and Wu measured that gap cleanly, and found it is large, negative and remarkably persistent.
Jul 13, 2026
Trades Beget Trades: Cartea, Jaimungal and Ricci on High-Frequency Market Making
Paper ExplainedOrder flow arrives in bursts, and one trade makes the next one more likely. Build that into your quoting model and the market maker's optimal behaviour changes completely.
Jul 13, 2026
The Crowd Was Right: Stock Opinions on Social Media Actually Predict Returns
Paper ExplainedAmateur investors writing stock articles on the internet sounds like a recipe for noise. Chen, De, Hu and Hwang found their collective view predicted returns and earnings surprises.
Jul 13, 2026
XGBoost: The Engineering That Made Boosting Win Everything
Paper ExplainedThe maths of gradient boosting already existed. Chen and Guestrin made it fast, regularized and robust to missing data, and it promptly took over applied machine learning.
Jul 13, 2026
Naming the Factors: Chen, Roll and Ross Connect Stocks to the Economy
Paper ExplainedStatistical factors have no names, which makes them hard to trust. Chen, Roll and Ross tried the opposite approach: start with real economic variables like inflation and industrial production, and see which ones stocks actually pay you to bear.
Jul 13, 2026
Sparse Signals: When the Lasso Found Real Alpha in One-Minute Returns
Paper ExplainedChinco, Clark-Joseph and Ye let a lasso hunt through every stock's recent returns for one-minute forecasts, and the odd, fleeting predictors it found turned out to be news.
Jul 13, 2026
Ten Times Worse: Chopra and Ziemba on Which Input Errors Actually Hurt
Paper ExplainedIf you can only get one input right, get the expected returns right. Chopra and Ziemba measured just how much more damage a mistake there does than a mistake anywhere else.
Jul 13, 2026
How Do You Measure Diversification? Choueifaty and Coignard Gave It a Number
Paper ExplainedEveryone says diversification is the only free lunch. Almost nobody can define it. Choueifaty and Coignard proposed a ratio, then built the portfolio that maximizes it.
Jul 13, 2026
Your Risk Model Was Right for the Wrong Reason: Christoffersen on Interval Forecasts
Paper ExplainedA risk model that breaks its limit exactly five percent of the time can still be dangerously wrong, if all the breaches arrive on the same terrible week. Christoffersen built the test that catches it.
Jul 13, 2026
The Boring Stocks Won: Clarke, de Silva and Thorley on Minimum-Variance Portfolios
Paper ExplainedBuild the calmest possible portfolio of US stocks, ignoring returns entirely, and you get much lower risk with no loss of return. Finance theory says that should not happen.
Jul 13, 2026
It Was Never About the Cash Flows: Cochrane's Discount Rates
Paper ExplainedJohn Cochrane's presidential address argued that almost everything that moves asset prices is not news about future profits, but changes in the return investors demand.
Jul 13, 2026
One Tent-Shaped Factor: Cochrane and Piazzesi on Bond Risk Premia
Paper ExplainedCochrane and Piazzesi found a single combination of forward rates that predicts the returns on every Treasury bond, and it is invisible to standard term structure models.
Jul 13, 2026
The Paragraph They Quietly Changed: Lazy Prices and the Signal Hiding in 10-K Edits
Paper ExplainedCompanies copy and paste last year's annual report. When they bother to change the wording, something is wrong, and nobody notices for months.
Jul 13, 2026
The Missing Factor: Why Nobody Can Explain Credit Spread Moves
Paper ExplainedCollin-Dufresne, Goldstein and Martin tested every variable theory says should drive credit spreads. Almost none of the movement was explained, and what was left over marched in lockstep across every bond.
Jul 13, 2026
How Do You Value a Thing With No Cash Flows? Cong, Li and Wang on Tokenomics
Paper ExplainedA token pays no dividend, so discounted cash flow is useless. Cong, Li and Wang built the model that values a token from the demand to actually use it, and found adoption follows an S-curve.
Jul 13, 2026
Post or Cross, and Where? Cont and Kukanov on Optimal Order Placement
Paper ExplainedOptimal execution tells you how much to trade. It never tells you how. Cont and Kukanov solved the decision every trader actually faces: limit or market, and on which exchange.
Jul 13, 2026
It Is Not the Trades, It Is the Imbalance: Cont, Kukanov and Stoikov
Paper ExplainedEveryone models price impact using trades. This paper shows that what actually drives short-term price moves is the imbalance of everything happening at the top of the book, including the orders that never trade.
Jul 13, 2026
The Order Book as a Queue: Cont, Stoikov and Talreja
Paper ExplainedForget informed traders and strategic games. Model the order book as a set of queues with orders arriving and leaving at random, and you can compute the odds of what happens next.
Jul 13, 2026
Companies That Grow Fast Make Bad Investments
Paper ExplainedCooper, Gulen and Schill found that the single best predictor of poor future stock returns is not valuation or profitability, but how fast a company grew its balance sheet.
Jul 13, 2026
Quoting a Price Is Writing Free Options: Copeland and Galai on Adverse Selection
Paper ExplainedCopeland and Galai realised that a posted bid and ask are two free options handed to the world, and the spread is the premium you must charge to survive them.
Jul 13, 2026
Three Averages Beat Everything: Corsi's HAR Model
Paper ExplainedCorsi forecast volatility using yesterday's, last week's and last month's averages. That is the whole model, and it embarrasses far more sophisticated competitors to this day.
Jul 13, 2026
Support Vector Machines: Draw the Line With the Widest Possible Margin
Paper ExplainedCortes and Vapnik asked which of the infinitely many lines separating two groups is the right one, and their answer, the widest gap, dominated machine learning for a decade.
Jul 13, 2026
The Spread Hiding in the High and the Low: Corwin and Schultz
Paper ExplainedCorwin and Schultz noticed that the daily high is almost always a buy and the daily low is almost always a sell, and built a spread estimator out of that one observation.
Jul 13, 2026
Rates That Cannot Go Below Zero: the Cox-Ingersoll-Ross Term Structure
Paper ExplainedCIR rebuilt the yield curve from an actual economy rather than a hedging trick, and got a short rate that keeps itself above zero and gets calmer as it falls.
Jul 13, 2026
Pretending Nobody Cares About Risk: Cox and Ross Invent Risk-Neutral Valuation
Paper ExplainedCox and Ross noticed that if an option can be hedged, its price cannot depend on how much investors fear risk, so you may as well assume they do not fear it at all.
Jul 13, 2026
Options Priced With Nothing but Arithmetic: the Binomial Tree
Paper ExplainedCox, Ross and Rubinstein found a way to price options using only addition and multiplication, and in doing so made the logic of Black-Scholes visible to everyone.
Jul 13, 2026
Just Ask Google: Measuring Investor Attention With Search Data
Paper ExplainedAttention was always assumed and never measured. Da, Engelberg and Gao realised that when a retail investor is interested in a stock, they type its ticker into Google.
Jul 13, 2026
You Cannot Have Everything: Dai and Singleton Audit the Affine Models
Paper ExplainedDai and Singleton organised every affine term structure model into a family tree and found a painful trade-off: you can model volatility, or you can model correlations, but not both.
Jul 13, 2026
Heads I'm a Genius, Tails I Was Unlucky: Overconfidence and Self-Attribution
Paper ExplainedDaniel, Hirshleifer and Subrahmanyam showed that investors who overrate their own research, and take credit for wins while blaming luck for losses, will produce momentum and long-run reversal all by themselves.
Jul 13, 2026
Momentum's Dirty Secret: It Crashes
Paper ExplainedMomentum earns steady profits for years and then loses a decade of them in a couple of months. Daniel and Moskowitz showed exactly when those crashes happen, and that you can see them coming.
Jul 13, 2026
Is It the Company, or the Company It Keeps?
Paper ExplainedFama and French said value stocks earn more because they move together with a risk factor. Daniel and Titman ran a clever test and concluded it is the characteristic itself that pays, not the risk.
Jul 13, 2026
A Century of Chart Patterns, Put on Trial: Sullivan, Timmermann and White
Paper ExplainedThey tested nearly 8,000 technical trading rules on 100 years of Dow data, and asked whether the winners were skill or just the best of a very large lottery.
Jul 13, 2026
Yesterday's Losers, Tomorrow's Winners: Does the Stock Market Overreact?
Paper ExplainedDe Bondt and Thaler bought the market's most hated stocks, shorted its most loved ones, and found that the crowd's enthusiasm reliably runs out.
Jul 13, 2026
DeepLOB: Teaching a Neural Network to Read the Order Book
Paper ExplainedZhang, Zohren and Roberts built a deep network that predicts short-term price moves from raw limit order book data, and found it worked on stocks it had never seen.
Jul 13, 2026
The Market Can Stay Irrational: Noise Trader Risk
Paper ExplainedDe Long, Shleifer, Summers and Waldmann showed that irrational traders create a risk all their own, one that scares off the smart money and lets mispricing survive.
Jul 13, 2026
Trading Volatility Without an Opinion on Direction: the Variance Swap
Paper ExplainedDemeterfi, Derman, Kamal and Zou showed that a specific weighted basket of options gives you pure exposure to volatility, with no view on where the market goes. That result is why the VIX exists.
Jul 13, 2026
Just Split It Evenly: The Paper That Showed 1/N Beats the Fancy Models
Paper ExplainedDeMiguel, Garlappi and Uppal tested 14 sophisticated portfolio models against the dumbest possible rule, put an equal amount in everything, and the dumb rule held its own.
Jul 13, 2026
Building a Tree That Already Knows the Smile: Derman and Kani
Paper ExplainedDerman and Kani took the binomial tree and grew it backwards out of market prices, producing a tree that reproduces the volatility smile by construction.
Jul 13, 2026
Forecasting a Curve by Forecasting Three Numbers: Diebold and Li
Paper ExplainedDiebold and Li turned Nelson-Siegel's static curve-fitting formula into a forecasting machine, by treating its three parameters as things that move through time.
Jul 13, 2026
Is My Forecast Actually Better Than Yours? Diebold and Mariano
Paper ExplainedModel A has a lower error than Model B. Is that a real edge, or just luck? Diebold and Mariano built the test that answers the question everyone was eyeballing.
Jul 13, 2026
Why Squaring Returns Was a Mistake: Ding, Granger and Engle
Paper ExplainedEveryone modelled squared returns because the maths was convenient. Three researchers checked whether the data agreed, and found the market's memory is strongest when you do not square anything at all.
Jul 13, 2026
Testing the Square-Root Law Where Nobody Expected It: A Million Bitcoin Metaorders
Paper ExplainedBitcoin in 2014 had no institutional market makers, no regulation and barely any arbitrageurs. The square-root law of market impact held anyway, which tells you something profound.
Jul 13, 2026
Beaten by a Coin Flip: Duffee and the Failure of Affine Forecasts
Paper ExplainedThe most sophisticated interest rate models in finance predicted future yields worse than assuming nothing changes. Duffee found the culprit and fixed it.
Jul 13, 2026
Why So Many Rate Models Have Formulas: Duffie and Kan's Affine Class
Paper ExplainedVasicek and CIR both produce closed-form bond prices. Duffie and Kan explained why, and mapped out the entire family of models that share the magic.
Jul 13, 2026
The One Trick That Made Credit Pricing Easy: Duffie and Singleton's Adjusted Discount Rate
Paper ExplainedDuffie and Singleton found a way to price risky bonds using exactly the same machinery as safe bonds, just by bending the discount rate to swallow the default risk.
Jul 13, 2026
One Model That Fits Every Option: Dupire's Local Volatility
Paper ExplainedDupire showed that the volatility smile does not just have to be tolerated, it can be inverted: the market's own option prices tell you exactly what volatility must be at every price and every date.
Jul 13, 2026
The Oldest Alarm in Econometrics: Durbin-Watson
Paper ExplainedOne number, printed under every regression for seventy years, that tells you whether your errors have a memory. Ignoring it is how researchers discover spurious relationships.
Jul 13, 2026
What Are the Odds the Next Trader Knows Something? The PIN Model
Paper ExplainedEasley, Kiefer, O'Hara and Paperman found a way to count informed traders you can never see, using nothing but the daily tally of buys and sells.
Jul 13, 2026
Pull Yourself Up By Your Bootstraps: Efron's Idea That Changed Statistics
Paper ExplainedHow do you measure the uncertainty of an estimate when the maths is impossible? Efron's answer was to resample your own data, over and over, and just look.
Jul 13, 2026
Squeezing More Power from a Weak Test: Elliott, Rothenberg and Stock
Paper ExplainedUnit root tests are famously bad at detecting slow mean reversion. Three authors worked out how much better any test could possibly be, then built one that gets close.
Jul 13, 2026
When Volatility Shocks Never Fade: Engle and Bollerslev on Persistence
Paper ExplainedFit GARCH to almost any market and the parameters nearly add up to one, which means today's shock still matters a year from now. Engle and Bollerslev took that seriously and built IGARCH.
Jul 13, 2026
Correlations Move Too: Engle's Dynamic Conditional Correlation
Paper ExplainedModelling volatility for one asset is easy. Modelling how a hundred assets move together used to be impossible. Engle's two-step trick made it routine.
Jul 13, 2026
Drawing the Curve of Fear: Engle and Ng on the Impact of News
Paper ExplainedEvery volatility model implies a picture of how today's surprise moves tomorrow's volatility. Engle and Ng drew that picture, gave it a name, and used it to referee the whole GARCH family.
Jul 13, 2026
The Bond Market's Recession Alarm: Estrella and Hardouvelis
Paper ExplainedEstrella and Hardouvelis showed that the slope of the yield curve forecasts real economic activity better than the professional forecasters do, which is why an inverted curve terrifies everyone.
Jul 13, 2026
The Forward Rate Is Not a Forecast: Fama and Bliss
Paper ExplainedFama and Bliss showed that when forward rates are high, it is mostly not because the market expects rates to rise. It is because bonds are paying you extra to hold them.
Jul 13, 2026
Three Wasn't Enough: the Fama-French Five-Factor Model
Paper ExplainedTwenty-two years after inventing the three-factor model, Fama and French admitted it was missing something and added two more ingredients: how profitable a company is, and how fast it is growing its assets.
Jul 13, 2026
Do the Factors Work Abroad? Fama and French Check
Paper ExplainedFama and French took size, value and momentum to four regions of the world. Value and momentum showed up nearly everywhere, Japan was the awkward exception, and global models failed.
Jul 13, 2026
Fama-MacBeth: The Regression Trick That Runs Half of Quant Finance
Paper ExplainedFama and MacBeth set out to test the CAPM and invented a two-step regression procedure so useful that it outlived the theory it was designed to test.
Jul 13, 2026
Efficiency Forces the Shape: Farmer, Gerig, Lillo and Waelbroeck on Why Impact Is Concave
Paper ExplainedMarket impact is concave and then decays. This paper argues that is not a coincidence of plumbing but a logical consequence of markets being unpredictable.
Jul 13, 2026
Taming the Factor Zoo: Is Your New Factor Actually New?
Paper ExplainedHundreds of factors have been published. Feng, Giglio and Xiu built a statistical test that asks whether a new one adds anything at all, and most of them do not.
Jul 13, 2026
Neither Forever Nor Fleeting: FIGARCH and the Long Memory of Volatility
Paper ExplainedVolatility shocks do not vanish in a week, but they do not last forever either. Baillie, Bollerslev and Mikkelsen built the model that lives in the awkward middle.
Jul 13, 2026
Counting the Crime on the Blockchain: How Much Bitcoin Is Illegal?
Paper ExplainedFoley, Karlsen and Putnins used police seizures and darknet market addresses as seed data, then traced the blockchain outward to estimate what share of Bitcoin activity was criminal.
Jul 13, 2026
Same Choice, Different Words, Opposite Answer: The Framing of Decisions
Paper ExplainedTversky and Kahneman proved that simply rewording a decision, with no change to the actual outcomes, can flip people's preferences completely.
Jul 13, 2026
The Boring Stocks Won: Betting Against Beta
Paper ExplainedTextbook finance says riskier stocks should earn more. Frazzini and Pedersen showed the opposite has happened for decades, and pinned the blame on investors who cannot borrow.
Jul 13, 2026
Gradient Boosting: Building a Great Model Out of a Chain of Bad Ones
Paper ExplainedFriedman showed that if you keep training small models to fix the mistakes of the model before them, you end up with something remarkably powerful.
Jul 13, 2026
One Company, Two Prices: The Royal Dutch and Shell Puzzle
Paper ExplainedTwo stocks entitled to the same cash flows traded at persistently different prices for decades, and each one drifted with the mood of the country it happened to be listed in.
Jul 13, 2026
Two Currencies, Two Interest Rates: Garman and Kohlhagen Price FX Options
Paper ExplainedCurrency options broke Black-Scholes because a currency pays interest while you hold it. Garman and Kohlhagen found the fix, and it is simpler than you would guess.
Jul 13, 2026
Twins That Drift Apart: The Academic Test of Pairs Trading
Paper ExplainedWall Street had been quietly trading pairs of similar stocks for decades. Gatev, Goetzmann and Rouwenhorst finally tested the folklore on forty years of data, and it worked.
Jul 13, 2026
Your Impact Model Might Be a Money Machine: Gatheral on No-Dynamic-Arbitrage
Paper ExplainedPick the wrong combination of impact shape and impact decay and your model implies you can print money by trading in circles. Gatheral worked out which combinations are legal.
Jul 13, 2026
Volatility Is Rough: the Discovery That Broke Fifty Years of Models
Paper ExplainedGatheral, Jaisson and Rosenbaum measured how jagged volatility actually is, found it far rougher than every model assumed, and accidentally explained the smile that nothing else could.
Jul 13, 2026
An Option on an Option: Geske and the Hidden Leverage of Equity
Paper ExplainedGeske priced options on options, and in the process explained why volatility rises when stocks fall, twenty years before anyone called it the leverage effect.
Jul 13, 2026
The GRS Test: One Number That Tells You Whether Your Factor Model Works
Paper ExplainedTesting whether twenty-five portfolios all have zero alpha by checking twenty-five t-statistics is a recipe for fooling yourself. Gibbons, Ross and Shanken built the single joint test that finance still uses to grade every asset pricing model.
Jul 13, 2026
The Volatility Switch That Only Flips on Bad Days: GJR-GARCH
Paper ExplainedGlosten, Jagannathan and Runkle added one simple on-off switch to GARCH so that only losses get an extra volatility kick, and stumbled onto an uncomfortable finding about risk and reward.
Jul 13, 2026
Splitting the Spread in Two: Glosten and Harris on What You Are Actually Paying For
Paper ExplainedThe bid-ask spread is not one fee. Glosten and Harris built a way to separate the part that is pure overhead from the part that is the fear of trading against someone smarter.
Jul 13, 2026
Was the Electronic Order Book Always Going to Win? Glosten's Prophecy
Paper ExplainedIn 1994, Glosten argued that an open electronic limit order book is not just one market design among many. It is the one that competitors cannot undercut.
Jul 13, 2026
Does A Cause B? Granger's Modest, Powerful Answer
Paper ExplainedGranger sidestepped the philosophy of causation entirely and asked a question data can actually answer: does knowing A's past help you predict B's future?
Jul 13, 2026
The Regression That Lies: Granger and Newbold on Spurious Results
Paper ExplainedTwo random walks with nothing to do with each other will produce a beautiful, highly significant regression. Granger and Newbold showed this, and half of empirical economics had to be re-examined.
Jul 13, 2026
Was the 2017 Bitcoin Boom Printed Out of Thin Air? Griffin and Shams on Tether
Paper ExplainedGriffin and Shams followed the blockchain and found that freshly issued Tether flowed into Bitcoin right after price dips, propping the market up. One entity did most of it.
Jul 13, 2026
Skill Times the Square Root of Breadth: Grinold's Fundamental Law
Paper ExplainedYou can be a great investor with a terrible hit rate, as long as you make enough independent bets. Grinold turned that idea into the one formula every active manager should know.
Jul 13, 2026
The Paradox at the Heart of Efficient Markets: Grossman and Stiglitz
Paper ExplainedIf prices already reflect all information, nobody has any reason to gather information, and then prices can't reflect it. Markets can only be efficient if they are a little bit inefficient.
Jul 13, 2026
The Machine Learning Horse Race: Gu, Kelly and Xiu Test Everything on Stock Returns
Paper ExplainedThey fed nearly a century of stock data into every major machine learning model and asked a blunt question: which one actually predicts returns?
Jul 13, 2026
The Market Maker's Real Enemy: Gueant, Lehalle and Fernandez-Tapia on Inventory Risk
Paper ExplainedMaking markets is easy until you are stuck holding the thing nobody else wants. This paper turned the market maker's nightmare into closed-form quotes you can actually compute.
Jul 13, 2026
Queue Priority Is the Whole Game: Guilbaud and Pham on Limit and Market Orders
Paper ExplainedMost market making models let you quote any price you like. Real markets have ticks, queues, and the brutal fact that being second in line means you do not get filled.
Jul 13, 2026
The Dataset That Ate the Literature: Gurkaynak, Sack and Wright
Paper ExplainedThree Fed economists published the daily US Treasury yield curve back to 1961, and gave it away. It became the shared foundation of nearly all modern bond research.
Jul 13, 2026
The Model That Fixed the Hedges: SABR and Managing Smile Risk
Paper ExplainedHagan and colleagues showed that local volatility models predict the smile will move the wrong way, which corrupts every hedge, and built SABR to fix it.
Jul 13, 2026
"Why You Should Never Use the Hodrick-Prescott Filter"
Paper ExplainedHamilton wrote a paper whose title is the entire argument, and then proved it: the most popular detrending tool in macroeconomics manufactures cycles out of nothing.
Jul 13, 2026
Two Worlds, One Series: Hamilton's Regime-Switching Model
Paper ExplainedMarkets do not behave the same way all the time. Hamilton built a model where the world secretly flips between states, and taught it to figure out which state we are in without ever being told.
Jul 13, 2026
Estimating Without a Full Model: Hansen's GMM
Paper ExplainedMost estimation methods demand that you specify the entire probability distribution of your data. Hansen showed you only need a few things you believe should average out to zero.
Jul 13, 2026
The Hansen-Jagannathan Bound: A Speed Limit Every Asset Pricing Model Must Obey
Paper ExplainedHansen and Jagannathan found a way to test economic models without committing to any particular one: markets themselves reveal a minimum amount of volatility any valid model must have, and most models fail it badly.
Jul 13, 2026
330 Models Walk Into a Horse Race: Does Anything Beat GARCH(1,1)?
Paper ExplainedHansen and Lunde tested 330 volatility models against the simplest one in the family. The plain vanilla version held its own, with one instructive exception.
Jul 13, 2026
Hansen's Fix: Why Padding Your Search With Bad Strategies Hides the Good One
Paper ExplainedWhite's Reality Check had a flaw: adding useless strategies to your search made it harder to detect a genuinely good one. Hansen showed how to repair it.
Jul 13, 2026
No Free Lunch: Harrison and Kreps Find the Grammar of Arbitrage
Paper ExplainedHarrison and Kreps proved that 'no arbitrage' and 'there exists a fair-odds probability' are the same statement, turning option pricing into a branch of probability theory.
Jul 13, 2026
The Engine Room: Harrison and Pliska Build the Machinery of Continuous Trading
Paper ExplainedThe paper that gave derivatives pricing its mathematical foundations, and proved that being able to hedge anything is exactly the same as having only one fair-odds measure.
Jul 13, 2026
Give Your Sharpe Ratio a Haircut: Harvey and Liu on Honest Backtesting
Paper ExplainedYour backtested Sharpe ratio is inflated because you searched for it. This paper tells you exactly how much to cut it down.
Jul 13, 2026
Most Published Factors Are Probably False: Harvey, Liu and Zhu Raise the Bar
Paper ExplainedResearchers had published hundreds of factors that 'predict' stock returns. This paper showed the statistical test they all used was far too easy to pass.
Jul 13, 2026
Where Does the Price Really Get Made? Hasbrouck's Information Share
Paper ExplainedWhen one security trades in many places, which venue is actually discovering the price and which is just copying? Hasbrouck built the standard scoreboard.
Jul 13, 2026
Measuring the Speed Demons: Hasbrouck and Saar on Low-Latency Trading
Paper ExplainedNobody labels their orders as high-frequency. Hasbrouck and Saar found a clever way to detect the fast traders in raw message data, then asked what they do to the market.
Jul 13, 2026
How Much Does a Trade Actually Tell Us? Hasbrouck's Measure of Information Content
Paper ExplainedHasbrouck built a way to ask, of any single trade, how much of the price move it caused was permanent news and how much was noise that faded.
Jul 13, 2026
Model the Whole Curve at Once: Heath, Jarrow and Morton
Paper ExplainedHJM proved that once you choose how volatile forward rates are, no-arbitrage forces everything else. You do not get to pick the drift. It picks itself.
Jul 13, 2026
Did the Robots Make Markets Better? Hendershott, Jones and Menkveld Find a Natural Experiment
Paper ExplainedEveryone argued about whether algorithmic trading helped or hurt liquidity. These three found a clean experiment that could actually answer it.
Jul 13, 2026
The Workhorse: Heston's Closed-Form Stochastic Volatility Model
Paper ExplainedHeston let volatility be random, let it fall when the market rises, and still managed to get a formula you can compute in microseconds. That combination made it the industry standard.
Jul 13, 2026
Start From the Market, Not From Theory: the Ho-Lee Model
Paper ExplainedHo and Lee flipped interest rate modelling on its head: take today's yield curve as a fact, then ask how it is allowed to move. Every model desks actually use now does this.
Jul 13, 2026
Where Should I Quote? Ho and Stoll's Inventory Model of Market Making
Paper ExplainedThe first proper answer to the market maker's daily question: given the position I am stuck with, where exactly do I put my bid and my ask?
Jul 13, 2026
Long Short-Term Memory: Teaching a Network to Remember What Matters
Paper ExplainedNeural networks used to forget everything more than a few steps back. Hochreiter and Schmidhuber built a memory cell that could hold on, and it became the backbone of financial deep learning.
Jul 13, 2026
Separating the Signal from the Cycle: the Hodrick-Prescott Filter
Paper ExplainedHow do you split a wiggly economic series into 'the long-run trend' and 'the cycle around it'? Hodrick and Prescott gave an answer so convenient that it took over macroeconomics.
Jul 13, 2026
Ridge Regression: Being Deliberately Wrong to Be More Right
Paper ExplainedHoerl and Kennard proved something heretical in 1970: a biased estimator can beat the unbiased one. Half a century later it is the foundation of every regularized model in finance.
Jul 13, 2026
News Travels Slowly, Traders Chase It: Hong and Stein's Unified Theory
Paper ExplainedHong and Stein got momentum and reversal from two groups of ordinary, limited investors, without needing anyone to be psychologically broken.
Jul 13, 2026
The Rival Model: Hou, Xue and Zhang's q-Factors
Paper ExplainedInstead of hunting through data for patterns, these three authors started from a textbook theory of how firms decide to invest, and derived a four-factor model that digested most of the anomaly zoo.
Jul 13, 2026
We Tried to Replicate 447 Anomalies. Most Failed.
Paper ExplainedHou, Xue and Zhang rebuilt every published stock return anomaly they could find using careful methods. Nearly two thirds of them simply were not there.
Jul 13, 2026
Impact Must Be Linear, or Else: Huberman and Stanzl on Price Manipulation
Paper ExplainedIf your model of how trading moves prices is even slightly the wrong shape, it hands you a machine for making free money. Huberman and Stanzl proved which shape is the only safe one.
Jul 13, 2026
Best of Both Worlds: Hull-White and the Extended Vasicek Model
Paper ExplainedVasicek had good economics but the wrong prices. Ho-Lee had the right prices but bad economics. Hull and White welded them together, and desks have used the result ever since.
Jul 13, 2026
When Volatility Refuses to Sit Still: Hull and White's Stochastic Volatility
Paper ExplainedHull and White let volatility wander randomly on its own, and found that Black-Scholes systematically misprices options, in a pattern that looks exactly like the smile.
Jul 13, 2026
Why Tying the Optimizer's Hands Makes It Smarter: Jagannathan and Ma
Paper ExplainedBanning short sales is theoretically wrong: it can only make the portfolio worse. Jagannathan and Ma showed it makes portfolios better, and revealed the hidden reason why.
Jul 13, 2026
One Trick, Many Bonds: Jamshidian's Exact Bond Option Formula
Paper ExplainedAn option on a coupon bond looks hopelessly complicated. Jamshidian found the change of view that turns it into a bundle of simple options you already know how to price.
Jul 13, 2026
Stop Explaining Default, Just Price It: Jarrow and Turnbull's Reduced-Form Model
Paper ExplainedInstead of modelling why a company fails, Jarrow and Turnbull treated default as a random bolt of lightning and calibrated its odds straight from bond prices.
Jul 13, 2026
Jensen's Alpha: The Number That Told Fund Managers They Were Not Special
Paper ExplainedMichael Jensen invented a way to separate genuine skill from mere risk-taking, pointed it at 115 mutual funds, and found that after fees the average manager destroyed value.
Jul 13, 2026
Finding Every Hidden Anchor at Once: Johansen's Cointegration Test
Paper ExplainedEngle and Granger could test whether two wandering series were tied together. Johansen showed how to find all the invisible ropes binding a whole basket of them, in one shot.
Jul 13, 2026
Don't Trust Your Return Forecasts: Jorion's Bayes-Stein Shrinkage
Paper ExplainedHistorical average returns are terrible forecasts. Jorion showed that dragging them all toward a common anchor, deliberately making them less accurate individually, produces better portfolios.
Jul 13, 2026
How Risky Is Your Risk Number? Jorion on the Error Bars Around VaR
Paper ExplainedYour risk system reports a Value-at-Risk of 10 million dollars. Jorion asks the question nobody was asking: how confident are you in the 10?
Jul 13, 2026
Making the Unfittable Fittable: Joslin, Singleton and Zhu
Paper ExplainedTerm structure models were famously impossible to estimate reliably. JSZ found a way to rewrite them that makes estimation almost instant, and revealed something surprising about no-arbitrage along the way.
Jul 13, 2026
Three Mental Shortcuts That Break Your Brain: Heuristics and Biases
Paper ExplainedTversky and Kahneman catalogued the rules of thumb people use to judge probability, and showed exactly how each one fails in predictable, exploitable ways.
Jul 13, 2026
Counting Cars From Space: What Satellite Data Did to the Level Playing Field
Paper ExplainedHedge funds bought satellite photos of retailer parking lots, counted the cars, and knew the earnings before anyone else. The paper that measured exactly how much that was worth.
Jul 13, 2026
Your Trading Style Sets Your Trading Bill: Keim and Madhavan
Paper ExplainedTwo funds trade the same stock and pay wildly different costs. Keim and Madhavan showed the difference is not luck, it is what kind of investor you are.
Jul 13, 2026
Characteristics Are Covariances: Kelly, Pruitt and Su Reconcile Risk and Anomalies
Paper ExplainedDo cheap stocks earn more because they are riskier, or because the market is wrong? A machine learning twist on PCA suggests the answer is risk, and that the two camps were arguing past each other.
Jul 13, 2026
The Week the Quants Broke: Anatomy of the August 2007 Meltdown
Paper ExplainedIn one week of August 2007, quant equity funds that had nothing to do with subprime lost enormous amounts of money and then made most of it back. Khandani and Lo reconstructed what happened.
Jul 13, 2026
How to Actually Beat VWAP: Konishi's Optimal Slicing
Paper ExplainedIf you are graded against the volume-weighted average price, the safe play is to trade like the volume curve. Konishi worked out when you should not.
Jul 13, 2026
Flipping the Question: the KPSS Test and the Burden of Proof
Paper ExplainedEvery unit root test asks 'can you prove this series is stable?' Four authors asked the opposite question, and discovered that the honest answer to both is often 'I don't know.'
Jul 13, 2026
Optimization Isn't Broken, Your Inputs Are: Kritzman's Defense
Paper ExplainedEveryone concluded that equal weighting beats optimization. Kritzman, Page and Turkington argued the studies had been feeding optimizers absurd forecasts, and that with sane inputs optimization wins.
Jul 13, 2026
The Hidden Clock of Markets: Kyle and Obizhaeva's Microstructure Invariance
Paper ExplainedA sleepy utility and a frenzied tech stock look nothing alike. Kyle and Obizhaeva claim that if you measure time in the right units, they are the same market.
Jul 13, 2026
Value Works Because People Extrapolate: Contrarian Investment, Extrapolation, and Risk
Paper ExplainedLakonishok, Shleifer and Vishny argued that cheap stocks beat expensive ones not because they are riskier, but because investors keep projecting the recent past into the distant future.
Jul 13, 2026
Can the Market Add and Subtract? The 3Com and Palm Absurdity
Paper ExplainedFor months, the market valued 3Com's stake in Palm at more than all of 3Com, implying the rest of the company was worth less than nothing. Nobody could fix it, because you couldn't borrow the shares to short.
Jul 13, 2026
Honey, I Shrunk the Covariance Matrix: How Ledoit and Wolf Fixed Portfolio Optimization's Weakest Input
Paper ExplainedThe historical covariance matrix is a noisy mess, and optimizers eat the noise. Ledoit and Wolf showed how to pull the extreme numbers back toward sanity, on purpose, by exactly the right amount.
Jul 13, 2026
Who Started It? Lee and Ready's Rule for Telling Buys from Sells
Paper ExplainedThe tape tells you a trade happened but not who was the aggressor. Lee and Ready wrote the rule of thumb that half of empirical microstructure quietly depends on.
Jul 13, 2026
A Dollar of Stocks for Eighty Cents: The Closed-End Fund Puzzle
Paper ExplainedClosed-end funds trade at a discount to the stocks they hold, the discounts all move together, and they move with small-cap returns. Lee, Shleifer and Thaler said that is what sentiment looks like.
Jul 13, 2026
The Hedge That Eats Itself: Leland on Options and Transaction Costs
Paper ExplainedBlack-Scholes says hedge continuously. Leland pointed out that continuous hedging with real trading costs would cost you an infinite amount of money.
Jul 13, 2026
One Curve for Every Stock: Lillo, Farmer and Mantegna on Market Impact
Paper ExplainedBig stocks and small stocks look nothing alike, until you rescale them. Then every price impact curve collapses onto a single universal shape.
Jul 13, 2026
The Other Father of the CAPM: Lintner's Version of Risk and Return
Paper ExplainedSharpe usually gets the credit, but John Lintner derived the same risk-return law independently, and he did it while trying to answer a practical question: which corporate projects are actually worth funding?
Jul 13, 2026
Level, Slope, Curvature: Litterman and Scheinkman Find the Three Factors
Paper ExplainedLitterman and Scheinkman pointed a statistical microscope at bond returns and found that almost everything the yield curve does is three simple movements.
Jul 13, 2026
Crypto Is Not Gold, Not Stocks, Not Anything: Liu and Tsyvinski Run the Numbers
Paper ExplainedLiu and Tsyvinski tested cryptocurrency returns against every standard risk factor in finance. None of them worked. What did work was momentum and pure attention.
Jul 13, 2026
Did Your Model Leave Anything Behind? The Ljung-Box Test
Paper ExplainedA good time-series model should squeeze all the predictable structure out of the data, leaving pure noise. Ljung and Box built the standard check for whether it actually did.
Jul 13, 2026
You Can Profit From Reversals Without Anyone Overreacting
Paper ExplainedEveryone assumed contrarian trading made money because investors overreact. Lo and MacKinlay proved you could earn those profits even if no single stock overreacted at all.
Jul 13, 2026
Default Risk or Just Hard to Sell? Splitting the Corporate Bond Spread
Paper ExplainedLongstaff, Mithal and Neis used the young credit default swap market as a clean thermometer for default risk, and finally measured how much of a corporate bond's extra yield is about default and how much is about illiquidity.
Jul 13, 2026
A Regression Beats a Tree: Longstaff and Schwartz on American Options
Paper ExplainedLongstaff and Schwartz solved American option pricing by simulation with an idea so simple it is almost cheeky: run a regression to guess what holding on is worth.
Jul 13, 2026
When Rates Rise, Spreads Fall: Longstaff and Schwartz on Risky Debt
Paper ExplainedLongstaff and Schwartz built the first credit model where interest rate risk and default risk talk to each other, and found the surprising result that credit spreads shrink when rates go up.
Jul 13, 2026
Build the Family Tree First: Lopez de Prado's Hierarchical Risk Parity
Paper ExplainedMarkowitz's optimizer treats every asset as a potential substitute for every other one, which is why it goes haywire. HRP groups similar assets into a tree first, then allocates down the branches.
Jul 13, 2026
When Is a Liability Not a Liability? The Dictionary That Fixed Financial Text Analysis
Paper ExplainedResearchers were measuring the tone of company filings with a psychology dictionary that thinks the words 'cost', 'liability' and 'tax' are negative. In finance, they are just Tuesday.
Jul 13, 2026
The Lucas Tree: Why Asset Prices Are Really About Hunger
Paper ExplainedRobert Lucas built the simplest possible economy, one tree that drops fruit, and used it to show that an asset's price depends not on how risky it is but on whether it pays off when you are hungry.
Jul 13, 2026
How Long Is a Bond, Really? Macaulay and the Birth of Duration
Paper ExplainedA bond's maturity date tells you when the last payment arrives, not when your money actually comes back. Macaulay invented a better clock, and it still runs the bond market.
Jul 13, 2026
Time Runs at a Random Speed: the Variance Gamma Model
Paper ExplainedMadan, Carr and Chang got fat tails and skew not by adding jumps to a random walk, but by letting the clock itself tick at a random rate.
Jul 13, 2026
Why Do Prices Change? Madhavan, Richardson and Roomans Take Apart the Tick
Paper ExplainedA structural model of the trade-by-trade price that separates real news, the cost of immediacy, and the mechanical fact that order flow is predictable.
Jul 13, 2026
Equal Risk, Not Equal Dollars: The Math Behind Risk Parity
Paper ExplainedA 60/40 portfolio puts 60 percent of the money in stocks and around 90 percent of the risk. Maillard, Roncalli and Teiletche worked out the portfolio where every asset contributes the same amount of risk.
Jul 13, 2026
The Same Bitcoin, Different Prices: Arbitrage in Crypto Markets
Paper ExplainedBitcoin traded at wildly different prices on different exchanges for weeks at a time. Makarov and Schoar showed the gaps were real, huge, and explained almost entirely by where you live.
Jul 13, 2026
The Option With No Strike Price: Margrabe's Exchange Option
Paper ExplainedMargrabe priced the right to swap one asset for another, and discovered that when both sides are risky, the interest rate vanishes and only relative risk matters.
Jul 13, 2026
Publishing an Anomaly Is How You Kill It
Paper ExplainedMcLean and Pontiff tracked 97 published return predictors and found their profits fell by more than half after publication. Writing the paper destroys the trade.
Jul 13, 2026
The Equity Premium Puzzle: Stocks Pay Too Much, and Nobody Knows Why
Paper ExplainedMehra and Prescott showed that the extra return stocks have paid over safe bonds is so large that no sensible model of human risk aversion can explain it, and forty years later nobody has convincingly solved it.
Jul 13, 2026
Anatomy of a High Frequency Market Maker: Menkveld Opens the Books
Paper ExplainedMenkveld got the trading records of one large HFT and showed exactly how it made money: earn on the spread, lose on the position, repeat a thousand times a day.
Jul 13, 2026
Your Company's Debt Is an Option in Disguise: Merton's Structural Credit Model
Paper ExplainedMerton showed that owning stock in an indebted company is exactly like owning a call option on the company's assets, and that one insight turned credit risk into option pricing.
Jul 13, 2026
Merton's ICAPM: Why One Factor Is Never Enough When Life Goes On
Paper ExplainedThe CAPM assumes the world ends after one period. Merton asked what happens if it doesn't, and discovered that investors will pay up for assets that protect them against a worsening future, which is where multi-factor models come from.
Jul 13, 2026
When Prices Gap: Merton Puts Jumps Into Option Pricing
Paper ExplainedBlack-Scholes assumes prices glide. Merton asked what happens when they gap, and found that the perfect hedge quietly stops working.
Jul 13, 2026
How Much Should You Put in Stocks? Merton's Answer Is a Single Fraction
Paper ExplainedMerton solved the lifetime investing problem in continuous time and got a shockingly simple answer: hold a constant fraction of your wealth in stocks, and spend a constant fraction of your wealth each year.
Jul 13, 2026
The Optimizer That Maximizes Your Mistakes: Michaud's Markowitz Enigma
Paper ExplainedPortfolio optimizers are mathematically flawless and practically distrusted. Michaud explained the paradox: they systematically fall in love with your worst estimates.
Jul 13, 2026
Why Machine Learning Funds Fail: Lopez de Prado's Ten Autopsies
Paper ExplainedThe models are not the problem. Lopez de Prado lists the ten ways quant teams misuse machine learning, and most of them are about how research is organised, not which algorithm you picked.
Jul 13, 2026
What Is a Millisecond Worth? Moallemi and Saglam Price Latency
Paper ExplainedFirms spend fortunes to shave microseconds off their trading. This paper asks the obvious question nobody had answered: how much is that speed actually worth, in dollars?
Jul 13, 2026
Stop Guessing Volatility, Start Measuring It
Paper ExplainedFour authors turned volatility from a hidden quantity you infer with a fancy model into a number you simply observe, and then beat the fancy models with an almost embarrassingly simple one.
Jul 13, 2026
The Third Discoverer: Mossin and the Cleanest Proof of the CAPM
Paper ExplainedA young Norwegian economist wrote the shortest, tidiest derivation of the CAPM, and in doing so nailed down the one thing Sharpe and Lintner had left slightly vague: what 'equilibrium' actually means.
Jul 13, 2026
Nine Pages That Made Digital Money Work: The Bitcoin Whitepaper
Paper ExplainedDigital cash had one unsolvable flaw: you can copy a file. Nakamoto solved it by making the ledger public and making lying more expensive than telling the truth.
Jul 13, 2026
Bad News Hurts More: Nelson's EGARCH
Paper ExplainedStandard GARCH treats a 5% crash and a 5% rally as identical shocks. Nelson showed markets do not, and built the model that finally lets falling prices scare volatility more than rising ones.
Jul 13, 2026
The Paper That Made Economists Doubt the Long Run: Nelson and Plosser
Paper ExplainedIf recessions are temporary dips below a trend, they eventually heal. Nelson and Plosser found that most economic data says they do not heal at all.
Jul 13, 2026
Three Numbers Describe a Yield Curve: Nelson and Siegel
Paper ExplainedNelson and Siegel found a formula with a handful of parameters that draws almost any yield curve the market can produce. Central banks have used it ever since.
Jul 13, 2026
Letting the Machine Learn to Trade: Nevmyvaka, Feng and Kearns on Reinforcement Learning for Execution
Paper ExplainedInstead of assuming a model of the market and solving it, this paper let an algorithm learn how to execute orders by trial and error against a year and a half of real order book data.
Jul 13, 2026
The Six-Page Paper Everyone Cites: Newey-West Standard Errors
Paper ExplainedYour regression's coefficient is probably fine. Your t-statistic is probably a lie. Newey and West wrote the short fix that made overlapping-return studies honest.
Jul 13, 2026
Cheap Is Only Half the Story: the Gross Profitability Premium
Paper ExplainedNovy-Marx showed that a boring line near the top of the income statement, gross profits, predicts stock returns about as well as the famous value ratio, and that the two work beautifully together.
Jul 13, 2026
The Order Book Refills: Obizhaeva and Wang on Supply and Demand Dynamics
Paper ExplainedLiquidity is not a fixed cost you pay, it is a resource that regenerates. Once you model the refilling, the best way to trade a big order stops being a smooth trickle.
Jul 13, 2026
Caught in the Act: Odean Finds the Disposition Effect in 10,000 Real Accounts
Paper ExplainedOdean got hold of real brokerage records and proved investors sell winners far more readily than losers, and that the winners they sell go on to beat the losers they keep.
Jul 13, 2026
The Stocks You Sell Beat the Stocks You Buy: Do Investors Trade Too Much?
Paper ExplainedOdean checked whether investors' trades actually improved their portfolios. On average, the stocks they bought went on to lag the stocks they sold, before even counting commissions.
Jul 13, 2026
The Old Rules Do Not Apply: O'Hara on High Frequency Market Microstructure
Paper ExplainedO'Hara argues that machine markets are not just faster human markets. The concepts we inherited, the trade, the day, even the price, need rebuilding.
Jul 13, 2026
It Is Not Illiquidity That Scares You, It Is Liquidity Risk: Pastor and Stambaugh
Paper ExplainedPastor and Stambaugh argued the real danger is not that a stock is hard to trade, but that it becomes hard to trade exactly when everything else does too.
Jul 13, 2026
Your Volatility Model Comparison Is Probably Wrong: Patton on Imperfect Proxies
Paper ExplainedGrade volatility forecasts with the wrong scoring rule and you can crown the worse model as the winner. Patton worked out exactly which scoring rules are safe, and the list is short.
Jul 13, 2026
Paper Versus Reality: Perold and the Invention of Implementation Shortfall
Paper ExplainedYour backtest made money. Your fund did not. Perold explained exactly where the difference went, and gave the industry the number it still uses to measure it.
Jul 13, 2026
Buy High or Buy Low? Perold and Sharpe on What Rebalancing Really Does
Paper ExplainedRebalancing to a fixed mix and buying portfolio insurance are opposite strategies with opposite payoffs. Perold and Sharpe showed there is no free lunch in choosing between them.
Jul 13, 2026
One Big Shock Can Fake a Random Walk: Perron's Structural Break
Paper ExplainedEconomists had concluded that almost every macro series was a random walk. Perron showed that a single ignored event, like the 1929 crash, was enough to manufacture that conclusion out of thin air.
Jul 13, 2026
The Unit Root Test That Stopped Guessing: Phillips-Perron
Paper ExplainedDickey and Fuller told you to model the noise in your data before testing it. Phillips and Perron found a way to stop modelling the noise and just correct for it afterwards.
Jul 13, 2026
The Stationary Bootstrap: Resampling Data That Has a Memory
Paper ExplainedThe plain bootstrap destroys the time structure in financial data. Politis and Romano found a way to resample in blocks of random length that keeps it intact.
Jul 13, 2026
93 Papers, One Verdict: What Actually Forecasts Volatility
Paper ExplainedPoon and Granger read two decades of volatility forecasting research so you do not have to, and reported which methods win, which lose, and why so many comparisons were meaningless.
Jul 13, 2026
Putting a Number on Self-Deception: the Probability of Backtest Overfitting
Paper ExplainedA method that answers the question every quant should ask: what are the odds my best-looking strategy is just the luckiest of my failures?
Jul 13, 2026
Losses Hurt Twice as Much: Prospect Theory
Paper ExplainedKahneman and Tversky showed people don't judge outcomes by final wealth. They judge gains and losses against a reference point, and losses sting far more than equal gains feel good.
Jul 13, 2026
Pseudo-Mathematics: How to Manufacture a Beautiful Backtest Out of Pure Noise
Paper ExplainedFour mathematicians proved that with enough tries you can produce a stunning backtest from random data, and that most published strategies are probably exactly that.
Jul 13, 2026
Optimizing for the Tail: How Rockafellar and Uryasev Made CVaR Practical
Paper ExplainedEveryone agreed average-loss-in-the-tail was a better risk measure than VaR. Nobody could optimize it. Rockafellar and Uryasev found the trick that turned it into a simple linear program.
Jul 13, 2026
Roll's Critique: The Paper That Said You Can Never Test the CAPM
Paper ExplainedRichard Roll pointed out something devastating: every test of the CAPM ever run is really a test of whether your chosen index is efficient, and nobody has ever observed the thing the theory is actually about.
Jul 13, 2026
The Spread You Can See Without Seeing the Quotes: Roll's Implied Bid-Ask Estimator
Paper ExplainedRichard Roll showed that the bid-ask spread leaves a fingerprint in the price series itself, so you can estimate trading costs from closing prices alone.
Jul 13, 2026
Letting the Data Name the Factors: Roll and Ross Test the APT
Paper ExplainedRoss's arbitrage pricing theory said returns are driven by a handful of factors but refused to say what they were, so Roll and Ross let a statistical algorithm find them, and it found three or four.
Jul 13, 2026
Where Book-to-Market Came From
Paper ExplainedEight years before Fama and French, three practitioners published the book-to-price effect and the short-term reversal effect, and titled the paper with unusual confidence.
Jul 13, 2026
Jumps Are Loud but Forgettable: Roughing It Up
Paper ExplainedSplit volatility into the market's steady grind and its sudden shocks, and you learn something useful: the grind persists for months, the shocks are forgotten almost immediately.
Jul 13, 2026
Safety First: The Portfolio Theory That Got There Before Markowitz Was Famous
Paper ExplainedA.D. Roy published a portfolio theory in the same year as Markowitz, built on a far more human idea: investors do not want to optimize a tradeoff, they want to avoid disaster.
Jul 13, 2026
Fitting the Smile Without Breaking the Tree: Rubinstein's Implied Binomial Trees
Paper ExplainedRubinstein's version of the implied tree starts from the end and works backwards, choosing the smoothest distribution that fits the market rather than forcing an exact fit to noisy prices.
Jul 13, 2026
The 'A' in ADF: Said and Dickey's Augmented Unit Root Test
Paper ExplainedThe original Dickey-Fuller test only worked if you knew the exact structure of your data's noise. Said and Dickey proved you can approximate any noise well enough, and made the test usable on everything.
Jul 13, 2026
Time Does Not Diversify Risk: Samuelson's Uncomfortable Result
Paper ExplainedEveryone believes young investors should hold more stocks because they have time to recover. Samuelson proved that under standard assumptions, your horizon should not change your allocation at all.
Jul 13, 2026
Better to Fail Conventionally: Herd Behavior and Career Risk
Paper ExplainedScharfstein and Stein showed that managers copy each other on purpose, ignoring their own research, because being wrong alongside everybody else is far safer than being wrong alone.
Jul 13, 2026
130 Years of Turbulence, and No Good Explanation: Schwert on Why Volatility Changes
Paper ExplainedSchwert gathered stock market data back to 1857 and tried to explain why volatility rises and falls. The most striking result is how badly the obvious explanations fail.
Jul 13, 2026
The Shanken Correction: Why Your Factor Model's t-Stats Are Too Good
Paper ExplainedEvery factor test estimates betas first and then uses them as if they were facts. Shanken showed that ignoring the noise in that first step makes your final results look far more convincing than they really are.
Jul 13, 2026
Where the Sharpe Ratio Came From: Grading Funds on Return Per Unit of Worry
Paper ExplainedBefore 1966, funds were ranked by returns alone, which rewarded anyone willing to gamble. Sharpe proposed dividing return by risk, and accidentally created the most quoted number in all of finance.
Jul 13, 2026
Sell Your Winners, Marry Your Losers: The Disposition Effect
Paper ExplainedShefrin and Statman named the most expensive habit in retail investing: cashing in gains far too eagerly while clinging to losses until they rot.
Jul 13, 2026
Shiller's Excess Volatility: Stock Prices Move Far Too Much
Paper ExplainedShiller compared the wild swings of the stock market against the calm, steady dividends those prices are supposed to be forecasting, and found the market moves many times more than any rational forecast could justify.
Jul 13, 2026
Right, Early, and Fired: The Limits of Arbitrage
Paper ExplainedShleifer and Vishny explained why the smart money fails to fix mispricing: arbitrageurs trade with other people's capital, and that capital runs away exactly when the opportunity is best.
Jul 13, 2026
Let the Data Speak: Sims and the Vector Autoregression
Paper ExplainedSims looked at the giant macro models of his day, declared their assumptions 'incredible,' and proposed something radically humbler: just let every variable depend on the past of every other variable.
Jul 13, 2026
One Law for All Stocks: Sirignano and Cont Find a Universal Price Formation Model
Paper ExplainedThey trained a deep network on billions of market events and discovered that a single model, trained on all stocks together, beats a model tuned to each stock individually.
Jul 13, 2026
Not All Profit Is Equal: the Accruals Anomaly
Paper ExplainedSloan showed that earnings made of cash are far more durable than earnings made of accounting estimates, and that the market cheerfully fails to notice the difference.
Jul 13, 2026
The Bias Hiding in Every Predictive Regression: Stambaugh
Paper ExplainedRegressing returns on dividend yield seems harmless. Stambaugh showed that the very structure of that regression manufactures predictability that is not there.
Jul 13, 2026
Anomalies Live on the Short Side
Paper ExplainedStambaugh, Yu and Yuan showed that almost all the profit in stock market anomalies comes from the stocks you should sell, and only after periods when investors are euphoric.
Jul 13, 2026
Two Hundred Predictors, Four Factors: Stock and Watson's Diffusion Indexes
Paper ExplainedYou have hundreds of possible predictors and only a few hundred observations. Stock and Watson showed how to squeeze them all into a handful of factors and forecast better than anyone.
Jul 13, 2026
The Price of Immediacy: Stoll's Theory of What a Dealer Sells
Paper ExplainedHans Stoll argued that a market maker is not selling stock. They are selling immediacy, and the spread is the price of that service.
Jul 13, 2026
A Second Hump: Svensson and the Curve Central Banks Actually Fit
Paper ExplainedSvensson added one more bump to Nelson-Siegel and turned a curve-fitting formula into a tool for reading what the market expects from monetary policy.
Jul 13, 2026
The More Data You Use, the Worse It Gets: A Tale of Two Time Scales
Paper ExplainedRealized volatility should improve as you sample prices more finely. In practice it falls apart, because tick data is mostly noise. Three authors found a way to use the noise against itself.
Jul 13, 2026
The Other Way to Model Volatility: Taylor's Stochastic Volatility
Paper ExplainedGARCH says today's volatility is calculable from yesterday's returns. Taylor said volatility has a mind of its own. Two philosophies, and the second one is harder but arguably more honest.
Jul 13, 2026
Counting Gloomy Words: Tetlock Turns a Newspaper Column Into a Trading Signal
Paper ExplainedTetlock counted the negative words in one Wall Street Journal column each day and found that media pessimism pushed prices down temporarily before they bounced back.
Jul 13, 2026
Money Is Not Fungible: Thaler's Mental Accounting
Paper ExplainedThaler showed people file money into separate mental folders and refuse to move it between them, which breaks the most basic assumption in economics.
Jul 13, 2026
From Blackjack Tables to Wall Street: Thorp on Actually Using the Kelly Criterion
Paper ExplainedEd Thorp took a formula from information theory, used it to beat casinos, then used it to run a hedge fund. His survey explains what the Kelly criterion really promises, and what it does not.
Jul 13, 2026
The Lasso: A Regression That Fires Its Own Useless Variables
Paper ExplainedTibshirani found a way to make a regression automatically set the coefficients of worthless predictors to exactly zero, solving variable selection and overfitting in one stroke.
Jul 13, 2026
Trend Following, Finally Explained: Time Series Momentum
Paper ExplainedForget comparing stocks to each other. Just ask whether an asset went up over the last year, and if so, buy it. Moskowitz, Ooi and Pedersen found this works on nearly every futures market on earth.
Jul 13, 2026
Tobin's Separation Theorem: Everyone Owns the Same Portfolio, Just Different Amounts
Paper ExplainedTobin proved that choosing which risky assets to own and choosing how much risk to take are two completely separate decisions, which is why your cautious grandmother and a hedge fund should hold the same stocks.
Jul 13, 2026
The Liquidity You See Is Not the Liquidity There Is: Toth, Bouchaud and the Square-Root Law
Paper ExplainedWhy does a large order cost the square root of its size? Because the order book you can see is a tiny sliver of a hidden, V-shaped pool of latent liquidity.
Jul 13, 2026
Bet on Your Best Ideas Without Betting the Farm: The Treynor-Black Model
Paper ExplainedYour analysts have opinions on twenty stocks. The market has thousands. Treynor and Black worked out exactly how to blend a handful of strong views into an index portfolio without wrecking it.
Jul 13, 2026
The CAPM Paper Nobody Published: Jack Treynor's Lost Manuscript
Paper ExplainedJack Treynor derived the CAPM before Sharpe, circulated it as a typescript, never published it, and watched three other men win a Nobel Prize for the idea.
Jul 13, 2026
Can Fund Managers Time the Market? Treynor and Mazuy Built a Test
Paper ExplainedA genuine market timer should be aggressive in rallies and defensive in crashes, which means their returns should curve upward. Treynor and Mazuy went looking for that curve and mostly found a straight line.
Jul 13, 2026
The Same Two Trades, in Every Market on Earth
Paper ExplainedAsness, Moskowitz and Pedersen took value and momentum out of the US stock market and ran them on bonds, currencies, commodities and foreign equities. Both worked almost everywhere, and they hedge each other.
Jul 13, 2026
One Rate to Rule Them All: Vasicek and the First Modern Yield Curve Model
Paper ExplainedVasicek showed that if you model just the overnight rate and forbid free money, the entire yield curve follows. It was the Black-Scholes moment for bonds.
Jul 13, 2026
Why Supply and Demand Move the Yield Curve: Vayanos and Vila
Paper ExplainedStandard theory says who buys a bond cannot affect its price. Vayanos and Vila built the model in which it can, and gave central bankers the theory behind quantitative easing.
Jul 13, 2026
Toxic Flow: VPIN and Measuring Adverse Selection in Machine Time
Paper ExplainedWhen markets got too fast for the clock, Easley, Lopez de Prado and O'Hara rebuilt the informed-trading gauge to run on volume instead of time.
Jul 13, 2026
When Some Errors Are Bigger Than Others: White's Robust Standard Errors
Paper ExplainedOrdinary regression assumes every data point is equally noisy. Financial data laughs at that. White showed how to get honest uncertainty without ever modelling the noise.
Jul 13, 2026
White's Reality Check: How to Tell If Your Best Strategy Is Just the Luckiest One
Paper ExplainedA bootstrap procedure that tests whether the winner of your strategy search actually beats the benchmark, or whether someone was always going to win.
Jul 13, 2026
Three Jobs of Money, and Bitcoin Fails All Three: Yermack's Verdict
Paper ExplainedMoney has to do three things. Yermack ran Bitcoin through each test in turn and concluded it works as a speculative asset, not as a currency.
Jul 13, 2026
Beyond the Square Root: When the Industry's Favourite Formula Breaks
Paper ExplainedThe square-root law of market impact fits beautifully over a narrow range of order sizes. Zarinelli and colleagues zoomed out and found something that fits far better.
Jul 13, 2026
Don't Tell the Test Where to Look: Zivot and Andrews
Paper ExplainedPerron fixed unit root testing by telling the test when the break happened. Zivot and Andrews pointed out that choosing the break date after looking at the chart is data mining, and built the version that finds it for you.
Jul 13, 2026
The Elastic Net: What to Do When Your Predictors Are All Saying the Same Thing
Paper ExplainedThe lasso picks one variable from a group of correlated ones and arbitrarily kills the rest. Zou and Hastie found the fix, and it matters enormously in finance.
Jul 13, 2026
Fast or Slow? The Art of Selling a Huge Position: Almgren-Chriss
Paper ExplainedSell a giant block of stock quickly and you crush the price; sell it slowly and the market might move against you. This paper found the sweet spot.
Jul 6, 2026
Where Should a Market Maker Set Its Prices? Avellaneda-Stoikov
Paper ExplainedA market maker has to quote a buy and a sell price at once, and manage the pile of stock it accidentally accumulates. This 2008 paper solved how.
Jul 6, 2026
Fixing Markowitz's Fragile Math: the Black-Litterman Model
Paper ExplainedMarkowitz's portfolio math was brilliant but wildly oversensitive to your inputs. Two Goldman Sachs researchers found an elegant way to tame it.
Jul 6, 2026
The Formula That Priced the Unpriceable: Black-Scholes
Paper ExplainedThe 1973 paper that showed how to put a fair price on an option, and accidentally launched a trillion-dollar industry.
Jul 6, 2026
The Volatility Model the Whole Industry Actually Uses: GARCH
Paper ExplainedA 1986 tweak to Engle's idea that made volatility forecasting simple enough for everyone, and it's still the everyday workhorse decades later.
Jul 6, 2026
Are Star Fund Managers Actually Skilled? the Four-Factor Model
Paper ExplainedCarhart added momentum to the Fama-French model and used it to ask a brutal question: do winning mutual funds keep winning because of skill, or luck and cheap fees?
Jul 6, 2026
When a Beautiful Backtest Is a Mirage: The Deflated Sharpe Ratio
Paper ExplainedThe 2014 paper explaining why a stunning backtest is usually a statistical illusion, and how to discount it once you admit how many strategies you tried.
Jul 6, 2026
Will It Come Back, or Just Keep Wandering? The Dickey-Fuller Test
Paper ExplainedThe 1979 paper that gave us a way to tell whether a price series drifts off forever like a random walk, or gets pulled back toward home like a stretched spring.
Jul 6, 2026
Why Calm Markets Turn Stormy: Engle and the Science of Volatility Clustering
Paper ExplainedThe 1982 paper that noticed markets have quiet spells and panicky spells, and built the first model that could see a storm coming.
Jul 6, 2026
Two Drunks and a Dog: The Idea Behind Pairs Trading
Paper ExplainedThe 1987 paper that explained how two wandering, unpredictable prices can still stay tethered together, the statistical bedrock of pairs trading.
Jul 6, 2026
Is the Price Always Right? the Efficient Market Hypothesis
Paper ExplainedThe paper that argued market prices already bake in everything we know, so consistently beating the market is far harder than it looks.
Jul 6, 2026
Beyond the Market: the Fama-French Three-Factor Model
Paper ExplainedThe CAPM said only market risk matters. Fama and French showed that small companies and cheap 'value' stocks earn extra, and rewrote how we measure risk.
Jul 6, 2026
Why There's a Gap Between Buy and Sell Prices: Glosten-Milgrom
Paper ExplainedThe bid-ask spread isn't greed, it's a tax the market maker charges to protect itself from people who know more than it does.
Jul 6, 2026
Winners Keep Winning: the Momentum Effect
Paper ExplainedThe paper that showed stocks which have gone up recently tend to keep going up, a stubborn pattern that shouldn't exist if markets were perfectly efficient.
Jul 6, 2026
How Much to Bet: The Kelly Criterion
Paper ExplainedA Bell Labs scientist used information theory to answer the oldest question in gambling and investing, how big should your bet be?
Jul 6, 2026
Trading in the Dark: Kyle's Model of the Informed Trader
Paper ExplainedHow does someone who knows a secret cash in without giving the game away? Kyle's 1985 paper cracked the hidden logic of informed trading and market depth.
Jul 6, 2026
The Coin That Isn't Quite Fair: Cracks in the Random Walk
Paper ExplainedThe 1988 paper that ran a clever statistical test and found the stock market isn't a pure coin-flip after all, there's a faint memory in the noise.
Jul 6, 2026
Don't Put All Your Eggs in One Basket: Markowitz and Modern Portfolio Theory
Paper ExplainedThe 1952 paper that turned 'diversify' from folk wisdom into math, and started the whole field of quantitative portfolio management.
Jul 6, 2026
The Rulebook Behind the Formula: Merton's Rational Option Pricing
Paper ExplainedPublished the same year as Black-Scholes, Merton's paper found the deeper logic and general laws that make option pricing hold together.
Jul 6, 2026
Many Engines of Return: the Arbitrage Pricing Theory
Paper ExplainedIf a stock's return depends on more than just 'the market,' what should it earn? Ross's answer built the foundation of modern factor investing.
Jul 6, 2026
How the Market Prices Risk: the CAPM
Paper ExplainedThe paper that gave us a single number, beta, to measure how much market risk a stock carries, and a rule for what return that risk should earn.
Jul 6, 2026
What Quants Actually Do All Day (and What They Don't)
EssayForget the movies. A grounded, jargon-free look at what a working quant's job really involves, and the myths worth dropping before you chase one.
Jul 5, 2026
Position Sizing: The Boring Skill That Decides Who Survives
EssayEveryone obsesses over what to buy. The survivors obsess over how much. A gentle, math-light intro to why bet size matters more than bet choice, and the Kelly intuition behind it.
Jul 4, 2026
Paper Trading to Real Money: The Gap Nobody Warns You About
EssayYour strategy crushed it on paper. Then you went live and it fell apart. That gap is real, predictable, and has a name for each part of it. Here's what changes when the money is real.
Jul 3, 2026
Signal vs Noise: The Hardest Skill in Quant
EssayMarkets are mostly random noise with a faint signal hidden inside. Telling the two apart is the whole job, and your own brain is wired to get it wrong. A fishing story.
Jul 2, 2026
How to Break Into Quant Without a Fancy Degree
EssayNo PhD from a top school? You're not locked out. A realistic look at the paths in, what actually matters to the people hiring, and how to build proof you can do the work.
Jun 30, 2026
Risk: Why 'How Much Can I Lose?' Beats 'How Much Can I Make?'
EssayBeginners obsess over returns. Survivors obsess over risk. A plain-English intro to drawdowns, ruin, and why the first question a pro asks is always about the downside.
Jun 28, 2026
Retail Quant: What You Can and Can't Do From a Laptop
EssayYou're not going to out-compute a hedge fund from your kitchen table. But that's not the whole story. An honest look at what edges are actually realistic for a DIY quant.
Jun 26, 2026
The Math You Actually Need to Start (and the Math You Don't)
EssayScared off by talk of stochastic calculus? Good news: the math that actually gets you started is smaller and friendlier than the internet makes it sound. Here's the honest list.
Jun 24, 2026
Why Most Trading Strategies Stop Working
EssayYou found something that works. Then it stops. That's not bad luck, it's the market doing exactly what it's designed to do. A plain-English look at crowding and alpha decay.
Jun 22, 2026
How to Read a Backtest Without Fooling Yourself
EssayA backtest is the easiest place in all of finance to lie to yourself. Here are the traps, lookahead, survivorship, costs, overfitting, explained with everyday examples.
Jun 20, 2026