It has been hypothesized that momentum might be rationally explained as a consequence of the cross-sectional variation of unconditional expected returns. Stocks with relatively high unconditional expected returns will on average outperform in both the portfolio formation period and in the subsequent holding period. We evaluate this explanation by first removing unconditional expected returns for each stock from raw returns and then testing for momentum in the resulting series. We measure the unconditional expected return on each stock as its mean return in the whole sample period. We find momentum effects vanish in demeaned returns.

The expectations hypothesis of the term structure has been decisively rejected in a large empirical literature that spans several decades. In this paper, using a newly constructed dataset of synthetic zero-coupon bond yields, we show that evidence against the expectations hypothesis is substantially weaker in data generated after the widespread publicity of its failure. These results are consistent with the idea that asset pricing anomalies tend to disappear once they are widely recognized.