Transparency is a feature. This page explains what this measures and why — in plain terms. The precise formulas and numeric conventions are documented in our internal methodology; the summary here is deliberate, not an omission.
Cumulative return is the total growth of an investment over a span of time, built up by chaining each period's return one after another as if every gain (or loss) were reinvested into the next period — the standard geometric-compounding view rather than a simple sum of the periods. A value of zero means you ended where you started; positive means net growth, negative means net loss.
It is a horizon figure, not an annual rate: it reports the full change across whatever window of periods you feed it, and it makes no assumption about how often those periods occur — you supply the return series, and daily, monthly, or annual data are all treated the same. To convert it to a per-year pace, use the separately documented CAGR.
