A study conducted by data analytics firm Inalytics has found that selling stocks in response to company earnings announcements is nearly two-an-a-half times more likely to add value compared to selling at any other time. This according to an article in Institutional Investor published last spring.
The study was reportedly a follow-up to a 2019 academic paper that analyzed the trading ability of portfolio managers (based on the selling activity of 271 institutional portfolios from January 2015 onward). The Inalytics study showed that stock sales rarely add value in general, with 79% of portfolios losing out on potential gains from selling shares at the wrong time—findings that echoed those of the 2019 study reflecting that portfolio managers displayed stock picking skill but underperformed “substantially” when selling stocks.
The Inalytics study also found that when stock sales occurred in response to an earnings announcement, 48% of portfolios added value. But the paper stipulated that “the same people who on the one hand are successful at announcement trades” are “unsuccessful when selling for other reasons,” the article reports.