Michael J. O'Sullivan is a corporate insider who has filed 113 SEC Form 4 insider transactions across 2 companies since 2017. The most recent filing shows the insider bought $250.5K of BRK.B on May 6, 2026. Across all open-market trades the lifetime net is −$60.4M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $12.7M across reported positions.

"Disclosed insider exposure" sums this person's most-recently-reported share counts across each company they're an insider in, multiplied by the current underlying price. It is not net worth — it misses retail holdings, private investments, real estate, index funds, and any company where the person isn't an SEC-reporting insider. For informational purposes only.