What Happens If You Miss the Best Days?

Read that last row again. Miss the 30 best days out of 6,591 and you lose money. That is 30 days out of 26 years — 0.46% of all trading sessions. Less than half a percent of the days account for more than 100% of the returns. Everything else is noise.

Critics of this analysis point out that it’s one-sided. If missing the best days destroys your returns, wouldn’t missing the worst days supercharge them? They’re right — in theory:

Missing the 10 worst days would have turned $10,000 into $108,124 — a ten-bagger. This is true. But it is also irrelevant, because of the pattern we identified in Episode 11: the best days and the worst days are the same days.

To miss the worst days, you would have had to sell before October 13, 2008 (−9.03%) and then buy back before October 13, 2008 (+11.58%). You would have had to sell before March 12, 2020 (−9.51%) and buy back before March 13, 2020 (+9.29%). The timing required is not merely difficult — it is paradoxical. The sell signal and the buy signal arrive on consecutive days, often separated by less than 24 hours.

The academic literature confirms this. A 2020 study by J.P. Morgan Asset Management found that six of the ten best days in the S&P 500 over the previous 20 years occurred within two weeks of the ten worst days. Our data shows the same pattern across 82 years: the best and worst cluster so tightly that no implementable trading strategy can reliably capture one while avoiding the other.

Let’s make this concrete. Here are the 10 best days since January 2000. Every one of them was covered in this series. Ask yourself: would you have been invested on these days?

Every single one of the 10 best days occurred during conditions that would have made any rational person consider selling. Banks were failing. A pandemic was spreading. Tariffs were escalating. The economy was shutting down. These were not days when you felt good about being invested. They were days when every instinct screamed to sell.

That is the cruelest feature of the +4% day: it arrives precisely when you least want to own stocks. The rally of October 13, 2008 came one week after the Dow had its worst week ever. The rally of March 24, 2020 came the day after the S&P closed at a level that represented a 34% decline in 23 trading days. The rally of April 9, 2025 came after four days of tariff-driven selling that erased 12% of the index’s value.

The “missing the best days” analysis is sometimes dismissed as a straw man: nobody misses only the best days. A market timer who sells during a crisis also avoids some of the worst days. True. But the timing problem is more fundamental than this objection suggests.

The entry problem. Selling is easy. Deciding when to buy back is the challenge. Every study of market timing shows the same result: investors who sell during panics tend to wait too long to reinvest. They wait for “confirmation” that the crisis is over, which means they wait until the recovery is well underway. By then, they have already missed the best days — because the best days are the beginning of the recovery.

The clustering problem. If the best and worst days were randomly distributed across time, a timing strategy might work: sell in bad months, buy in good months. But they are not randomly distributed. They cluster in the same weeks, often in the same days. You cannot sell Tuesday to avoid a −9% crash on Wednesday and buy back Wednesday afternoon to capture the +9% rally on Thursday. By the time you process the information and execute the trade, the move has already happened.

The asymmetry problem. Missing a +10% day costs you 10% of your portfolio permanently. That lost 10% compounds forever. Over 26 years at the S&P’s average return, that missing 10% would have grown to roughly 40%. Every missed best day inflicts permanent, compounding damage to your long-term wealth.

Across twelve episodes, we have examined every +4% day in S&P 500 history. We traced them from the forgotten postwar rallies of the 1940s through the policy-driven surges of the 2020s. We studied the stock movers, the breadth data, the catalysts, and the context. And we arrived at a conclusion that is simultaneously obvious and profound:

The greatest single-day rallies in market history occur at the moments of greatest fear. They are not rewards for courage. They are not predictable. They are not tradeable. They are the mathematical consequence of compressed springs releasing — of prices overshooting to the downside and snapping back when a catalyst arrives.

The practical conclusion is the simplest one possible: stay invested. Not because the market always goes up (it doesn’t). Not because crises aren’t real (they are). Not because selling is never rational (sometimes it is). But because the cost of missing the turn is permanent, the timing is impossible, and the best days live inside the worst markets.

Fifty-six days. Eighty-two years. One pattern. The best days and the worst days are the same days. You cannot have one without the other. And the only strategy that captures both is the simplest one of all: be there.