Running your own backtest

The backtester in the app takes a list of tickers with weights and tells you how that portfolio would have done. It runs on the daily closes we already hold. You can also ask for one in Ask in plain words.

What you enter#

What you get back#

• The curve of your portfolio next to the comparison.
• Total return, CAGR, volatility, Sharpe and max drawdown for both. See How each number is computed.
• A year-by-year table and how many years you beat the comparison.
• Each holding's own return and its weight at the end.
• The caveats that apply to this particular run.

When the test starts later than you asked#

If one of your tickers has no price before a certain date, the test starts there, and the result names the ticker that limited it. We do not invent prices for the missing stretch. Drop the ticker to test a longer period.

The bias you bring#

You are choosing these tickers today, knowing how they did. That is the strongest bias a backtest can have, and every run on hand-picked tickers carries a caveat saying so.

Ways to use it honestly#

• Test a portfolio you actually hold, to learn its worst fall and how it compares with simply holding the index.
• Compare two weightings of the same tickers. The hindsight is the same in both, so the difference means something.
• Compare rebalancing schedules for the same portfolio.
• Do not use it to prove that a stock you like was a good idea.