Ex-post (Latin for “after the fact”) has multiple meanings in different contexts. In finance, it denotes actual returns generated by an asset/ portfolio/ business/ security, etc. Ex-post returns are those that have already been realized, and as such are treated as historical returns. This measure of returns, that are generated in the past, is used as a predictor of period-to-period future returns, depending on specific common variables such as seasonality, trends, etc.

Ex-post returns are the opposite of ex-ante returns or expected/ forecasted returns.

In legal sense, ex-post is the opposite of ex-ante, which means “before the event/ before the fact/ prior to an occurrence.”