Missing the Top 10 Days — How Much Does It Cost?
Stepping out of the market when it feels scary, then stepping back in — common move. The data on what happens when those quick steps out skip the market's biggest up days is brutal.
When the market falls, stepping out for a bit and stepping back in later sounds like the smart move. Avoiding the danger zone feels rational. The catch is that the market's biggest up days usually cluster right after the big down days. Step away briefly, miss those days, and the long-term return gets cut more than people expect. Let's walk through the numbers.
What the JPM Guide data shows
JP Morgan publishes Guide to the Markets every year, and one statistic comes up repeatedly. The comparison between staying fully invested in the S&P 500 over 20 years and missing the best days.
From 2003 to 2022, holding S&P 500 straight through for 20 years produced about 9.8% annualized. Ten thousand dollars grew to about 65,000.
Now take the same 20 years and miss the top 10 days. The annualized drops to 5.6%. Ten thousand dollars grew to about 29,000. Roughly half the fully invested result.
Miss the top 20 days, and annualized falls to 2.6%. Top 30 days, 0.3%. Top 40 days, negative 1.7%. Top 50 days, negative 3.6%. Comparing 20 years fully invested to missing 50 days, the end result diverges by more than 13x.
This is one US S&P 500 dataset, but similar patterns repeat across other markets.
Why a handful of days swings the result this much
Twenty years equals roughly 5,000 trading days. Missing just 10 of them and watching the result get cut in half is hard to picture. The cause is that the market's biggest up moves cluster on a very specific handful of days.
Long-term return doesn't accumulate evenly day by day. A small number of large up days produce most of the total. Miss those, and the remaining thousands of days don't make up for it.
Compounding amplifies the gap. A 5% drop followed by a 5% gain doesn't bring you back to flat — it leaves a small loss. Miss a big up day, and the compounding starts one step behind. Twenty years of that being one step behind adds up into a major gap.
The big up days cluster next to the big down days
One more decisive pattern shows up here. The market's biggest up days sit very close to the biggest down days.
The JPM stats show that 7 of the top 10 days fall within 2 weeks of the bottom 10 days. The biggest rebounds tend to follow right after big drops.
During the 2008 financial crisis, some of the largest single-day gains on record arrived in the days right after the big drops. Same pattern showed up in March 2020 with COVID. The market fell 30% over a week, then rose more than 20% over the next week.
The problem this creates is clear. Pull out when the market drops because it feels scary, and you miss the rebound days that follow. Those days carry half your long-term return. That's what makes market timing one of the riskiest moves possible.
So market timing runs into a hard structure
Market timing sounds simple. Sell before it drops, buy back before it rises. Easy. The pattern above is what makes the actual attempt costly.
To pull off market timing, you need to get two things right.
First, get out right before the big drop starts. If you're already mid-fall, the loss is already taken.
Second, get back in right before the big rebound starts. Big rebounds usually come within days of the bottom. Miss those days, and your long-term return gets cut in half.
Hitting both points exactly is extremely hard. Multiple academic studies of US funds attempting market timing show that timing rarely beats fully invested over the long run consistently.
What this means for your portfolio
The conclusion the data points to is clear. The more time you spend out of the market, the higher the risk that your long-term return gets pulled down.
That's why long-term investors are generally guided to stay in the market. During scary periods, trimming weight a bit is one thing — fully exiting is rarely the recommendation.
If putting a lump sum in feels heavy, putting a steady monthly amount in works too. No market timing — just steady deposits. When the market falls, the same dollar amount picks up more shares, lowering the average cost.
If you're already in the market, the standard guidance is to stay through scary headlines. Adjusting weight a bit when fear runs hot is fine — fully exiting can reshape your long-term result in ways you don't want.
Wrapping up in one line
Missing the top 10 days over 20 years cuts the fully invested result roughly in half. Big up days cluster right after big down days, which is what makes market timing so risky. Staying in the market is the simplest answer the long-term data points to. Adjusting weight slightly is fine — fully walking away takes serious thought.
- This information is not investment advice.
- Past performance does not guarantee future results.
- Backtest results are simulations and may differ from actual trading outcomes.
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