Insider Trading by Sector

The eleven sectors here are the Global Industry Classification Standard, built by MSCI and S&P Dow Jones Indices and used by most institutional investors to organise the equity market. A company is placed by its principal business activity, judged mainly by where its revenue comes from, so the boundaries occasionally surprise: a payments network sits in Financials rather than Information Technology, and a large online retailer sits in Consumer Discretionary rather than in technology at all. Where we hold no GICS assignment for a filer, we map its SEC-assigned SIC code across a standard crosswalk, which is close but not identical, so treat a single company's placement as approximate and the aggregate as sound.

The first thing to internalise is that these columns are not symmetric. Selling exceeds buying in almost every sector in almost every quarter, and that is a fact about how executives are paid rather than a verdict on the market. Equity compensation arrives as grants and vesting options, so an executive who never forms an opinion about their own shares will still generate a stream of sales to cover withholding tax and to avoid holding most of their net worth in one stock. Nobody is ever handed shares by accident on the buy side. This is why the buy share of dollar flow is the column worth watching: it is the part of the picture that requires a decision.

Compare sectors against their own history rather than against each other. A sector of large, mature companies whose executives hold enormous vested positions will always show a low buy share, and a sector full of small companies where founders still own their stock will always show a high one. The signal is a shift: Energy running at three times its normal buy share, or Financials going quiet after a year of steady purchases, says more than a cross-sector league table ever will.

Seasonality is the other trap. Insiders are barred from trading during the blackout period their company sets around results, typically from a few weeks before quarter end until a day or two after the release. Since companies in the same sector tend to report in the same weeks, an entire sector can fall silent for reasons that have nothing to do with what its insiders think. A sector showing almost no activity is usually in blackout, not in despair, and the 90-day window here is deliberately long enough to span at least one full reporting cycle for most of them.

Use this page as a way in rather than as an answer. Open a sector to see which companies are behind its numbers, because a sector total is frequently one very large purchase in one company rather than a broad mood, and a single 10% owner building a position can move an entire sector's bar on its own. The company-level view is where the distinction between a trend and one large cheque becomes visible.