Every strategy that finished ahead of the index also spent long stretches behind it. Here is how long, strategy by strategy.
Hypothetical backtest, not live results
Hypothetical backtest, not live results. These figures come from testing rules on past prices. Nobody invested this money, and past performance does not guarantee future results. Stocks Not Stuff is research and education, not financial advice: nothing here is a recommendation to buy or sell anything.
· From the stored backtest
The question
A headline figure tells you where a strategy ended up. It says nothing about the years in between.
What does it look like along the way? How long could you sit behind a plain index fund, wondering whether the strategy has stopped working?
How we tested it
For every trading day in the test we compared two numbers: what the strategy's portfolio was worth, and what the same money in the S&P 500 was worth. If the strategy was worth less, that day counts as a day behind.
From that we took two measures. The first is the share of all days spent behind. The second is the longest unbroken run of days behind, which we turn into months at 21 trading days to a month.
The result
What it means
It is also why every screen shows the S&P 500 next to the strategy, in the bad months as well as the good ones. A bad stretch you were told to expect is easier to sit through than one that comes as a surprise.
What it does not prove
These are the bad stretches of one decade. Nothing limits the next one to the same length. It could be longer and deeper.
Your count would differ. Days behind are counted from the first day of the test. Someone who starts on another day gets a different number.
A long stretch behind can also be the start of a real failure. These figures cannot tell the two apart while it is happening. That is why a strategy that trails the index badly in live results is retired in public.
Nobody invested this money. It is a test on past prices, and live results are likely to be lower.
The longest unbroken stretch behind the S&P 500 in the ten years
Strategies
Buy the dip27 months · behind on 55% of days
Steady winners24 months · behind on 33% of days
Streak + breakout22 months · behind on 34% of days
Winning streak21 months · behind on 25% of days
Winners on sale18 months · behind on 23% of days
A random S&P 500 company each day
Random picks, run 150 months · behind on 90% of days
Random picks, run 269 months · behind on 96% of days
Random picks, run 361 months · behind on 92% of days
From the stored backtest run of 3 Nov 2026: $100 every trading day, 3 Nov 2016 to 3 Nov 2026. Hypothetical, not live results.
Over the ten years, Winners on sale, the lead strategy, was behind the S&P 500 on 23% of days. Its longest unbroken stretch behind was 372 trading days, about 18 months. The longest of any strategy was Buy the dip’s: 566 trading days, about 27 months.
Winners on sale against the same money in the S&P 500, over the ten years
+60%+40%+20%0%−20%
2017201820192020202120222023202420252026
▲ Ahead of the S&P 500▼ Behind itEnded 42% ahead
From the stored backtest run of 3 Nov 2026: $100 every trading day, 3 Nov 2016 to 3 Nov 2026. Hypothetical, not live results.
The ten-year figure hides a harder start. In the five-year test that begins in Nov 2016, Winners on sale was behind on 44% of days. It still finished that test ahead: 27.3% a year against 20.8%. For comparison, the random-pick runs were behind on 90% to 96% of days over the ten years.
Being ahead of the index is also not the same as being up. Over the same ten years Winners on sale’s worst drop was −36%. The index’s was −34%.
Every strategy in the test, at some point, spent at least 18 months in a row behind the index. So a long stretch behind is normal for these rules. It is not, by itself, a sign that something broke. Anyone following one of them should expect stretches like these.