BEAT THE COUCH · THE ARCHIVE · BLACK MONDAY
THE WINDOW: JAN 2, 1987 TO DEC 29, 1988 · 504 TRADING DAYS
On October 19, 1987 the market fell 20.5% in one day. A couch that bought in January 1987 and held still ended two years later with $12,187. Only 39.5% of 1,128 players beat it.
THE COUCH'S $10,000, DAY BY DAY, REAL DAILY DATA
October 19, 1987. The market lost 20.5% in a single session, the worst day in the series by a wide margin, worse than anything in 1929 or 2008. Two days later it gained 9.1%. Portfolio insurance, program trading, and a wall of panic all get blamed, and the argument is still going.
Now the part nobody remembers: a couch that bought in January 1987 and did nothing at all ended this window with $12,187, up +21.9%. The most famous crash in living memory is a dent in a two-year chart.
Look at the line above. The crash is the cliff. The recovery is the rest of it, and it happened while everyone was still explaining the cliff.
Player figures cover every game whose window started in 1987, not only the exact hand above, and come from the run export of August 28, 2026. A win counts as SKILL only if it beats 90% of 1,000 monkeys replaying the same window with the same trade count and the same time in the market. Across the ten windows in this archive players beat the couch 48.6% of the time, because these are the famous years. Across the whole ledger the couch wins 62% of 120,800 games.
Only 39.5% of 1,128 players beat the couch here, in the window containing the single worst day in market history. That is the joke of Black Monday. Knowing the crash is coming is worth nothing unless you also know the bounce is coming, and the bounce started 48 hours later while every headline in the world said sell.
Play this exact windowfree, no signup, about two minutes. Same two years, same data, no hindsight.About 20.5% in one session on October 19, 1987, the largest single-day drop in this data series, which runs from 1928. Two days later the market gained 9.1%.
Comfortably. In this game a couch that bought in January 1987 and never traded ended two years later with $12,187 of $10,000, up +21.9%, despite a 33% drawdown on the day itself.
Only 39.5% of 1,128 players beat the couch in windows starting in 1987, below the archive average, because getting out was only half the problem.
Method: real S&P 500 daily total returns, dividends included, calibrated to Damodaran's annual series; cash earns 3-month T-bills. The same data the game deals. See the evidence page for sources, and the full ledger for the whole ledger.
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Not financial advice. The couch is not licensed for anything.