Thurmond Mark C. 4

What Happened

• Mark C. Thurmond, Chief Executive Officer of Tenable Holdings, converted/exercised a total of 25,369 derivative units (RSUs/PRSUs/other restricted awards) into common stock on May 22, 2026 at $0.00 per share (these were vested awards, not open‑market purchases). To satisfy tax withholding obligations, the issuer withheld 12,268 shares at $25.45 per share, representing withholding proceeds of approximately $312,220. The remaining ~13,101 shares were issued to Mr. Thurmond net of withholding.

Key Details

• Transaction date: May 22, 2026; Form 4 filed May 26, 2026.
• Conversion/exercise entries coded "M" (exercise/conversion of derivative) — 25,369 shares acquired at $0.00.
• Withholding entries coded "F" (payment of exercise price or tax liability) — 12,268 shares withheld at $25.45, total ~$312,220.
• Shares owned after the transaction: not disclosed in the provided filing.
• Notable footnotes: F2 confirms withheld shares were used to satisfy income tax withholding and do not represent an open‑market sale; F3 describes each RSU equals one share; F4–F6 explain PRSU certification and payout percentages; F1 notes 820 shares were acquired under the ESPP in exempt transactions.
• Filing timeliness: Form filed May 26, 2026 (reports the May 22, 2026 transactions) — not marked as late in the filing.

Context

• This was a routine conversion/settlement of vested restricted and performance awards (derivative conversion), not an open‑market sale or purchase. The withholding of shares to cover taxes is a common cashless settlement mechanism and should be viewed as tax administration rather than an intentional sale of stock for investment reasons. Transaction codes: M = exercise/conversion of derivative; F = tax withholding/payment.