Bloomberg provides PX_BID and PX_ASK on a daily basis, but it's not clear exactly where these numbers come from. Are they closing bid and ask prices, or are they averaged over the entire day? For ...
Fama-Macbeth (1973) introduce a two stage cross-sectional regression method (http://en.wikipedia.org/wiki/Fama%E2%80%93MacBeth_regression). 1) If I was to regress stock prices (or returns) on a ...