What happened last time? › Stock markets
What happens when the Hang Seng is 10% below its 200-day average?
It has happened 25 times since 1987. A year after it began, the S&P 500 was up 17 of 25 times, with a median move of +10.8%. On an ordinary day in the same years the median was +11.1%, up 79% of the time.
Hang Seng: % above its 200-day average below -10. Not true on 2026-09-25.
What came next
| 1 month later | 1 year later | 3 years later | |
|---|---|---|---|
| S&P 500 | +1.0% 52% up · n 25 · normal +1.2% | +10.8% 68% up · n 25 · normal +11.1% | +41.2% 76% up · n 25 · normal +32.9% |
| Gold | +0.1% 52% up · n 25 · normal +0.0% | +8.1% 68% up · n 25 · normal +2.4% | +38.1% 72% up · n 25 · normal +12.4% |
| Oil | +5.9% 68% up · n 25 · normal +1.0% | -4.2% 48% up · n 25 · normal +5.8% | +21.8% 68% up · n 25 · normal +13.3% |
| 10-year yield (pts) | -0.07 pts 36% up · n 25 · normal -0.02 pts | -0.47 pts 32% up · n 25 · normal -0.23 pts | -0.83 pts 28% up · n 25 · normal -0.52 pts |
| Inflation, CPI y/y (pts) | +0.04 pts 56% up · n 25 · normal -0.00 pts | -0.43 pts 36% up · n 25 · normal +0.04 pts | -0.34 pts 44% up · n 25 · normal -0.31 pts |
| Unemployment rate (pts) | 0.00 pts 21% up · n 24 · normal 0.00 pts | -0.20 pts 40% up · n 25 · normal -0.30 pts | -0.90 pts 40% up · n 25 · normal -0.80 pts |
Median move after each episode began, how often it rose, and how many episodes had data. "Normal" is the same move from any trading day in the same years.
Every time it happened
- 2021-08-20 · true for 229 trading days · S&P 500 a year later: -4.8%
- 2020-03-12 · true for 27 trading days · S&P 500 a year later: +59.0%
- 2018-12-27 · true for 3 trading days · S&P 500 a year later: +30.2%
- 2018-09-10 · true for 36 trading days · S&P 500 a year later: +3.6%
- 2015-11-16 · true for 64 trading days · S&P 500 a year later: +6.2%
- 2015-08-21 · true for 32 trading days · S&P 500 a year later: +10.8%
- 2013-06-24 · true for 2 trading days · S&P 500 a year later: +24.0%
- 2011-08-08 · true for 93 trading days · S&P 500 a year later: +25.2%
- 2010-05-25 · true for 1 trading day · S&P 500 a year later: +22.9%
- 2008-06-12 · true for 201 trading days · S&P 500 a year later: -29.4%
- 2008-03-13 · true for 7 trading days · S&P 500 a year later: -42.5%
- 2008-01-22 · true for 1 trading day · S&P 500 a year later: -35.9%
- 2003-02-06 · true for 23 trading days · S&P 500 a year later: +36.3%
- 2002-12-30 · true for 1 trading day · S&P 500 a year later: +26.2%
- 2002-07-26 · true for 35 trading days · S&P 500 a year later: +17.1%
- 2002-02-07 · true for 1 trading day · S&P 500 a year later: -23.2%
- 2001-03-02 · true for 163 trading days · S&P 500 a year later: -8.3%
- 2000-11-24 · true for 6 trading days · S&P 500 a year later: -14.3%
- 2000-09-22 · true for 4 trading days · S&P 500 a year later: -33.3%
- 1997-10-21 · true for 227 trading days · S&P 500 a year later: +10.0%
- 1994-12-01 · true for 52 trading days · S&P 500 a year later: +35.2%
- 1994-07-05 · true for 6 trading days · S&P 500 a year later: +22.6%
- 1992-12-03 · true for 1 trading day · S&P 500 a year later: +8.1%
- 1989-06-05 · true for 36 trading days · S&P 500 a year later: +13.9%
- 1987-10-26 · true for 109 trading days · S&P 500 a year later: +24.0%
- 25 separate episodes: a new one starts after 30 days without a match, so one long selloff counts once.
- Try enough situations and one will look like an edge by chance.
- Macro numbers are as published at the time. Stocks include companies that later died.
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