PlainQuant

After an event

Pick an event to see what the market did in the weeks and months after each past time it happened. How it works →

Or ask about an index move, e.g. “Nasdaq falls 10% in 2 days” or “Hang Seng up 5% in a week”.

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US credit rating downgrade: what came after

Measure on: US · Hong Kong

The market here is the S&P 500, measured by the SPY fund with dividends added back · 2 times in our prices (2016-01-04 to 2026-10-30) · measured from that day's close

2 weeks4 weeks3 months
Any window+0.9% · 66%+1.8% · 70%+4.6% · 79%

“Any window”: the middle result, and how often the market was up, over every window of the same length since 2016-01-04, event or not.

Too few to summarise: we need 5 and our prices hold 2. Here is each one.

Each one (2), newest first
Date2 weeks4 weeks3 months
2025-05-16+0.2%+0.5%+7.9%
2023-08-01-2.3%+0.2%-6.8%