ex post是什么意思

问题如下：

Each composite of a GIPS-compliant firm must consist of:

选项：

A.multiple portfolios.

B.portfolios selected on an ex-post basis.

C.portfolios managed according to a similar investment strategy.

解释：

A composite is an aggregation of one or more portfolios managed according to a similar investment mandate, objective, or strategy. For example, if a GIPS-compliant firm presents performance for a global equity composite (the composite), the composite must include portfolios that are managed, or have historically been managed, according to the firm's global equity strategy. A is incorrect because a composite is an aggregation of one or more portfolios managed according to a similar investment mandate, objective, or strategy. A composite may consist of a single portfolio when it is the only portfolio managed according to a particular mandate. B is incorrect because the determination of which portfolio(s) to include in a composite should be done according to pre-established criteria (ex-ante basis), not after the fact (ex post basis).