Unraveling a Puzzle: The Case of Value Line Timeliness Rank Upgrades
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We examine a sample of Value Line’s timeliness rank upgrades that occur immediately following earnings announcements and find that pre-event price momentum has significant incremental explanatory power for post-event drift, after controlling for the level of earnings surprise. Therefore, the stock price drift following Value Line’s timeliness upgrades cannot be viewed as driven only by the post-earnings announcement drift phenomenon. Instead, these findings indicate that, among other factors, Value Line has been exploiting the price momentum effect for decades. Black (Financ. Anal. J. 29:10–14, 1973) clearly stated that it does indeed do this, but his assertion has not yet been verified as an explanation of the puzzling drift that follows Value Line rank upgrades.
Financial Markets and Portfolio Management