Thurmond Mark C.

Thurmond Mark C., co-chief executive officer of Tenable Holdings (TENB), has filed 61 Form 4 transactions, all in that single company. The pattern is one-sided: no open-market purchases, no acquisitions of shares for cash, and no sales back to the issuer. The total sell value across all filings is $937,948.44, but the recent transaction codes show that figure is not from discretionary selling. The most recent cluster, dated August 24, 2026, consists entirely of paired "M" and "F" codes. The "M" entries, valued at zero, represent option exercises. The "F" entries, which total roughly $416,376 across six separate line items, are shares withheld to cover tax obligations on those exercises. The same structure appears on May 22, 2026, with another set of option exercises and tax-withholding disposals totaling about $312,220. These are automatic transactions, not open-market sales. The only other recent filing is an "A" code grant on February 26, 2026, also valued at zero, which is compensation rather than a purchase. Across the full 61 filings, Thurmond has no "P" or "S" codes at all. His entire reported activity is mechanical: option exercises, tax withholding, and equity grants. The dollar values attached to the "F" codes are the only cash figures in the record, and they reflect the tax cost of vesting or exercising, not a directional bet on the stock.