Mark Zagorski

Mark Zagorski is a declared insider at 4 companies (chief executive); the most frequent names are DoubleVerify Holdings, Inc., Telaria, Inc. and Magnite, Inc. In total, 80 filings cover trades dated from 11 August 2017 to 30 September 2026.

Purchases make up the whole of the open-market record (9 purchases, €668k). Unlike grants, an open-market purchase is paid for by the insider, at the market price. The rest of the record consists of 26 share grants and 43 option exercises.

The median purchase comes to €34k. Clusters matter here: 3 out of 8 purchases overlapped with buying by a colleague within 30 days. Such overlaps are known as a cluster signal: distinct people reaching the same decision at about the same time. For 6 purchases whose 90-day window has closed, the share price was higher on day 90 than the day after publication in 17% of cases, with a median move of -9.7%. They describe history only and say nothing certain about the share price ahead.

The latest filing, published on 2 October 2026, reports an option exercise in DoubleVerify Holdings, Inc. The latest purchase dates back some time: it was published 494 days ago, on 17 June 2025. Typically, a trade is published a median of 2 days after it takes place. The legal deadline for a Form 4 is two business days after the transaction. These figures are compiled from regulatory filings published by SEC (Form 4). They describe what insiders did and are not a recommendation.