Ex Post alpha

CAIA
#1

Hello everyone!

I don’t understand the following sentence: if an ex ante alpha is zero, it indicates that the fund manager possesses no skil.

However, ex ante is it not describing before the fact? So we don’t know yet the pearformance of the portfolio manager. For me it should be the ex post alpha , if it is equal to zero, that will indicate if a fund manager hasn’t skill. Thank you !

#2

ex-post alpha may be attributable to luck and/or skill so you cannot say say ex-post alpha is representative of a managers skill since his excess returns could have just been random or lucky.