Insider buying before earnings: does it matter?
We looked at 1857 quarterly results releases since Oct 12, 2023 and compared how the stock reacted when company insiders had bought shares in the 30 days before, with how it reacted when they hadn't.
The comparison
Insiders bought in the 30 days before
+2.9% average 2-day reaction · 100% rose · median +1.3% · +3.0% vs. S&P 500 Next 30 days: +4.2% (+1.2% vs. S&P) 3 releases · small sample, read with careNo insider buying beforehand
+0.5% average 2-day reaction · 53% rose · median +0.3% · +0.2% vs. S&P 500 Next 30 days: +2.1% (-0.0% vs. S&P) 1854 releasesStock rising into results (+3% or more in 15 days)
+0.5% average 2-day reaction · 51% rose · median +0.2% · +0.3% vs. S&P 500 Next 30 days: +2.3% (+0.5% vs. S&P) 611 releasesStock falling into results (−3% or more)
+0.9% average 2-day reaction · 55% rose · median +0.9% · +0.7% vs. S&P 500 Next 30 days: +2.3% (-0.4% vs. S&P) 430 releasesInsiders bought AND the stock was falling
+0.4% average 2-day reaction · 100% rose · median +0.4% · -0.2% vs. S&P 500 Next 30 days: +2.0% (-3.2% vs. S&P) 1 releases · small sample, read with care The classic “buying the dip” setup.Insiders sold (and none bought) beforehand
+0.1% average 2-day reaction · 52% rose · median +0.5% · -0.0% vs. S&P 500 Next 30 days: +1.6% (+0.6% vs. S&P) 128 releases Sales are common and often pre-planned.Reaction = close on the first trading day after the 8-K results filing vs. the last close before it, covering both before-the-open and after-the-close releases. Insider trades are open-market purchases of at least the site's minimum size, by trade date.
How to read this
Most companies close a “trading window” for insiders in the weeks before results, so purchases shortly before earnings are uncommon. When they do happen they're often made by outside directors, or under pre-scheduled 10b5-1 plans set up months earlier. Nothing here suggests anyone traded on inside information.
These are averages over many companies and quarters. A single stock can do the opposite, and the smaller a group, the less its average means. Past reactions don't predict future ones.
Every case with insider buying before results
Wins and losses, newest first.
Facts from public SEC filings and market prices, not investment advice.