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Risk Measures

44 articles · 6 checkpoints · 25 deeper reads · 13 reference notes

Every article, in reading order

plant a flag as you finish each

Read these first

  1. The diversification you counted on when you built the portfolio is measured in calm markets, and calm-market correlations are not the correlations that show up when everything actually goes wrong at once.

  2. Instead of assuming a shape for tomorrow's losses, replay the last few hundred real market days through today's positions, sort the results, and read off the loss you exceed only rarely. Simple, popular, and quietly full of assumptions.

  3. A trading book holds thousands of different instruments, but their risk comes from a few dozen shared drivers. Mapping is the translation step that rewrites every position as a set of sensitivities to those drivers, so the whole book can be aggregated and measured.

  4. A VaR model makes a promise you can check: losses should breach the number on 1% of days and no more. Backtesting counts the breaches, and Kupiec's test decides whether the gap between promised and observed is ordinary bad luck or a broken model.

  5. A precise way to answer "how much of the portfolio's total risk does this one position actually cause," using a mathematical property that guarantees the pieces add up exactly to the whole.

  6. A statistical theory for the worst days specifically, built from the idea that the shape of extremes doesn't have to match the shape of the everyday, and that you can estimate a 1-in-1000-day loss from a lot fewer than 1000 bad days.

Then the rest

Reference notes13 short entries