Earnings drift relative to the surprise factor, the reaction in the minutes after the announcement, the relation to size of company, and its continuity and change is of great interest. Many people study it and try to predict the earnings and sales, and talk about the anticipatory moves before the announcement, and the subsequent moves after. There are numerous articles about it on ssrn, including 495 with the heading "earnings report" and almost all of them seem to leave out the question of ever changing cycles and are based on outdated data.

Typical of the research is a recent paper by Jiasun Li on moves after earnings announcements. He finds that if you put a limit order half way between bid and asked and follow the drift 1 minutes after the announcement, there are profits to be made. Bloomberg seems to have incorporated many of the academic papers and gives a history of the last 40 earnings reports classified by such things as the estimated earnings, the actual, the surprise, the price change, the p/e. It's amazing how many of the actual earnings, are proximate to the estimates. Also, the muted reaction of price to the earnings change is also notable.

Two exceptions are Hewlett Packard and Netflix which often seem to have prices changes of 10 to 40% in the day following the earnings release, but almost all the other changes are within 2 or 3%. Most of the studies show that transaction costs are very high relative to any regularities that exist, and as mentioned these are before taking account of ever changing cycles, and the tendency of any published research if it didn't have the numerous biases that they tend to have, to be vitiated by shrewd operators in the period after publishing.

One intelligent thing that a few of the papers do is to classify the earnings surprise by dividing by a denominator based on price change rather than earnings announced. Considering the intense focus on earnings reports and the many firms that provide the estimates and base their trading decisions upon it, and the small margin of superior or inferior performance that exists, the tendency of those who follow it to endeavor to create market neutral portfolios that would lose the entire upward drift of the market in a dysfunctional effort to reduce risk, one would consider that it is a fallow area for research and only an academic could afford to low increment to knowledge that would result from attempting to unravel the biases, regularities, and opportunities for profits. At least that's my opinion, and I am interested in any corrections, or augmentations that might be made to my preliminary thinking.





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