Any twelve months
The best and worst year this portfolio had, whichever day you started counting.
In the demo portfolio
-34.5% to +80.8%
How it is computed here
Every rolling window of 252 sessions, not just January to December.
Worked example
- Every 12-month window in the history: 1,309 of them, each starting one session later.
- Worst -34.5%, median +9.7%, best +80.8%.
- 29% of those twelve-month windows lost money.
Demo portfolio: four invented companies, generated prices, measured by the real engine. Past returns do not predict future ones.
Where it misleads
The 1st of January has no financial meaning — it is an administrative cut. The worst stretch a portfolio ever had almost never starts there, so a table of calendar years hides it.