Momentum Based on Day of Week

Are there interactions between stock return momentum and days of the week? In their March 2024 paper entitled “Same-Weekday Momentum”, Zhi Da and Xiao Zhang investigate how momentum interacts with days of the week. They first perform regression tests to evaluate abilities of same-day and other-day past returns to predict day-of-the-week momentum. They then evaluate economic significance of findings by comparing three trading strategies:

1. Standard Momentum – each month, reform a value-weighted hedge portfolio that is long (short) stocks that are in the top (bottom) tenth, or decile, of stocks with the highest (lowest) average monthly returns from 12 months ago to one month ago.
2. Same-Weekday Momentum – each weekday during a month, reform a value-weighted hedge portfolio that is long (short) the decile of stocks with the highest (lowest) average daily returns on the same day of the week from 12 months ago to one month ago.
3. Other-Weekday Momentum – each weekday during a month, reform a value-weighted hedge portfolio that is long (short) the decile of stocks with highest (lowest) average daily returns on other weekdays from 12 months ago to one month ago.

Using daily data for publicly listed U.S. stocks, excluding those priced less than $5 and those in the bottom tenth of NYSE market capitalizations, during 1963 through 2021 and daily equity fund/institutional trading data as available, they find that: (more…)