What if you bought the S&P 500 on the 2011 'Black Monday' US downgrade?
This uses real data to show what would have happened if you had invested a lump sum in the S&P 500 ETF (SPY) on August 8, 2011 — the 'Black Monday' when stocks plunged about 6.7% in a day right after the US lost its top credit rating (AAA) for the first time ever.
⚠️ Know the risk first
There were further declines right after entry, and recovery took time. The U.S. index recovered in about half a year this time, but recovery speed differs by event — buying at the 2008 or 2022 peaks took far longer.
What happened that day
On August 5, 2011, S&P downgraded the U.S. sovereign rating from AAA to AA+ for the first time ever. On the first trading day after, August 8, the S&P 500 plunged about 6.7% in a day, but U.S. stocks recovered pre-downgrade levels over roughly half a year.
Why this date
The buy date is August 8, 2011, the first trading day when stocks plunged 6.7% after the first-ever U.S. downgrade, computing 'what if you bought the index on the day of a mega-shock.'
Investment conditions
Asset · S&P 500 ETF (SPY) · lump-sum on the 2011 US-downgrade plunge day, then held long-term
Method · Lump-sum (all at once)
Period · 2011-08-08 ~ 2026-07-01
Amount · $7,407
As of · 2026-07-01
Key metrics
These results do not reflect taxes. Based on historical data.
Buy and final prices are shown in the asset's local currency (US & crypto $, Japan ¥, Korea ₩). Total invested and final value are in Korean won (₩).
Risk & recovery
As important as returns. This service does not hide maximum drawdown or loss periods.
Maximum drawdown (MDD)
-33.7%
Largest drop from peak
Longest loss period
0months
Months in loss: 0
Recovery period
15months
Growth over time
Invested principal (dashed) and portfolio value (solid). Values below match the calculation.
Total invested $7,407 → Final value $64,070 (+764.9%), Maximum drawdown (MDD) -33.7%
Why this period and asset
On August 5, 2011 (local time), the rating agency S&P downgraded the U.S. sovereign rating for the first time ever, from the top AAA to AA+. Shocked that even 'the safest' U.S. was downgraded, the S&P 500 plunged about 6.7% in a single day on the first trading day, August 8. Compounded by European debt-crisis fear, markets were badly shaken, but U.S. stocks recovered pre-downgrade levels over roughly half a year. It's a classic 'day of a mega-shock' case.
Interpreting the result
An index is diversified across hundreds of companies, so it tends to be relatively resilient to shock news. Check the final value and annualized return (XIRR) below, but note there were further declines right after entry and that recovery took time. 'The day of scary news' was not necessarily the worst buy date — but that is only knowable in hindsight. Buying the same index at the 2008 or 2022 peaks took far longer to recover — compare with the related cases.
Caveats & limits
This case does not mean 'buying on the day of bad news always wins.' The 2011 downgrade turned out to be only a roughly half-year shock to U.S. stocks; buying the same way at the 2008 or 2022 peaks brought far longer losses. Always review the maximum drawdown and loss periods. Figures use adjusted close and exclude exchange rates, fees, and taxes, and past results do not guarantee the future.
Event fact sources
- Standard & Poor's — US sovereign rating downgrade to AA+ (2011-08-05)
- Reuters, 2011 Black Monday market selloff coverage (2011-08-08)
Requested date vs actual trading date
If the event date is a holiday, the fill uses the next trading day's close. The 'effective trading date' below is the date actually used.
Data sources & limits
- Price data source: Yahoo Finance / FinanceDataReader
- Collected on: 2026-07-28
- Effective trading date: 2026-07-01
- Price basis: Adjusted close (reflects dividends and stock splits)
- Trading fees and taxes are not reflected — figures are pre-tax.
- Based on historical data; does not guarantee future returns.
Frequently asked questions
What does a US credit downgrade mean?
It's a downgrade of confidence in a nation's ability to repay its debt. In 2011, S&P cut the U.S. from the top AAA to AA+ for the first time ever, and markets were badly shaken by the shock that even 'the safest' U.S. was downgraded.
How far did it fall that day?
On the first trading day after the downgrade, August 8, 2011, the S&P 500 plunged about 6.7% in a single day. There were further declines afterward, but U.S. stocks recovered pre-downgrade levels over about half a year. Check the maximum drawdown metric below.
So should I buy every time bad news hits?
No. The 2011 downgrade was just a case where the shock, about half a year, was relatively brief. Buying the same index at the 2008 or 2022 peaks took years to recover. Each event differs, and this page recommends no trading rule.
Are FX and taxes reflected?
No. Exchange rates, trading fees, and taxes are not reflected — figures are pre-tax. In real index investing, USD/KRW moves and taxes would additionally affect results.
Related scenarios
📋 Results are based on historical data; past returns do not guarantee future returns.
📋 This service is provided for educational purposes to help you understand investing, not as investment advice.