The COVID Crash and the Dash for Cash

Between 20 February and 23 March 2020, the S&P 500 fell about 34% as COVID-19 shutdowns began. That part fits the pattern of every previous crash: bad news, falling stocks, investors seeking safety. What did not fit the pattern is what happened to the safe asset itself. In the second week of March, US Treasury bond prices also fell, even as stocks kept falling — the opposite of the "flight to quality" that normally sends Treasury prices up in a panic.

What happened

Date (2020)	Event
20 Feb - 9 Mar	Equities fall sharply; Treasuries rally as normal — a classic flight to safety
9-12 Mar	Treasury yields start rising even as equities keep falling — prices falling in both markets at once
12 Mar	Corporate bond markets seize up; bid-ask spreads across fixed income widen dramatically
15 Mar	Federal Reserve cuts rates to zero and announces $700bn of asset purchases over a weekend emergency meeting
23 Mar	Fed announces open-ended quantitative easing and a wide range of emergency lending facilities; markets begin to stabilize within days

The mechanism

The proximate cause was a simultaneous, economy-wide scramble for cash. Companies drew down credit lines in case revenue stopped. Investors facing margin calls and redemptions needed to raise cash fast. Foreign central banks and sovereign wealth funds needed dollars. Everyone reached for the same solution at once: sell the most liquid, highest-quality asset they held to raise cash immediately.

That asset was Treasuries. But "most liquid in normal times" does not mean "infinitely absorbable in a crisis." The dealers who normally intermediate Treasury trading (see Primary Dealers and Market-Making Obligations) had their own balance-sheet limits, tightened further by post-2008 capital rules, and could not warehouse the sudden volume of selling. With too many sellers and too little dealer capacity to absorb them, even Treasuries had to fall in price to clear. Leveraged relative-value trades betting on small pricing gaps between Treasury bonds and Treasury futures were forced to unwind into this illiquid market, adding still more selling exactly when there were no natural buyers.

The Federal Reserve's response was the largest and fastest in its history: rates to zero, unlimited quantitative easing, and a series of emergency facilities (including direct backstops for money-market funds and corporate bond markets) within about two weeks of the initial selloff. Markets stabilized almost as quickly as they had broken, which is itself evidence that the problem was a liquidity shortage rather than a solvency one — see The Standing Repo Facility, created in 2021 partly in response to this episode.

The lesson

"Safe asset" and "liquid asset" are not the same claim, and a crisis can separate them precisely when you need them both. Treasuries remained safe throughout — nobody doubted the US government would pay its debts — but they briefly stopped being reliably liquid, because everyone wanted to sell the same thing at the same moment and dealer balance sheets could not stand in the middle of that flow. The same failure mode as Volmageddon, February 2018 recurs here at a much larger scale: a mechanically-driven, synchronized flow (there, ETP rebalancing; here, economy-wide cash-raising) overwhelmed the capacity of the market it needed to trade through.