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© 2026 InsiderTradingScreener.com. Data from SEC EDGAR Form 4 filings.For informational purposes only. Not financial advice.
Home/Insiders/SEIFERT THOMAS J

SEIFERT THOMAS J

Insider

Insider
Total trades
166
Bought (open market)
$0
Sold (open market)
$86M
Acquired (grants)
$10K
Tickers traded
2
Thomas J. Seifert, chief financial officer of Cloudflare, has filed 166 Form 4 transactions across two companies, with a clear and consistent selling bias. His total open-market sales reached $85.98 million, while he recorded zero open-market purchases. The only acquisition value on file, $9,999.78, came from a grant or award, which is compensation rather than a conviction buy. The pattern holds in recent activity: 17 sales in the latest period and no buys. The recent trades all involve Cloudflare (NET) and cluster around monthly option exercises and same-day sales. On September 17, 2026, Seifert exercised options with no reported value and sold shares in eight separate transactions totaling $2.99 million. The individual sales ranged from $31,890 to $878,080. A week earlier, on September 15, he had $963,365 in shares withheld to cover taxes, an automatic event tied to vesting. The August cycle followed the same shape: an option exercise on August 17, followed by seven sales worth $3.07 million, plus a tax-withholding event of $929,656 on August 15. The largest single transaction came on August 4, 2026, when Seifert sold $16.17 million of NET stock. That sale followed an option exercise valued at $2.46 million on the same date. The recurring sequence, exercise then sell, is mechanical in nature. The sales are open-market dispositions, but they are paired with option exercises and tax withholdings, which means the cash proceeds are not purely discretionary. The data shows a CFO who regularly converts vested options into cash, with no recent open-market buying to offset the outflow.

AI-assisted summary

12-month activity

Monthly buy vs sell totals from SEIFERT THOMAS J's Form 4 filings.

BuysSells
Show data table
MonthBuysSellsFilings
October 2025$0$2.1M7
November 2025$0$8.1M16
December 2025$0$2M7
January 2026$0$1.8M9
February 2026$0$7.7M21
March 2026$0$2.2M8
April 2026$0$2M10
May 2026$0$2M11
June 2026$0$2M9
July 2026$0$2.7M12
August 2026$0$19.6M13
September 2026$0$3M11

Recent trades

Most recent Form 4 filings by SEIFERT THOMAS J.

  • SEIFERT THOMAS Jtraded10,000 shares ofNETSep 17 · filed Sep 21Details
  • SEIFERT THOMAS Jsold100 shares ofNETat $318.9$32KSep 17 · filed Sep 21Details
  • SEIFERT THOMAS Jsold300 shares ofNETat $328.04$98KSep 17 · filed Sep 21Details

Explore insider screeners

Latest CEO & CFO PurchasesLatest CEO & CFO SalesDirector PurchasesOfficer PurchasesTop Purchases This WeekTop Sales This WeekTop Officer Buys (Month)10% Owner Filings10b5-1 Planned TradesDiscretionary TradesBuy/Sell RatiosPolitician-Insider Overlap
SEIFERT THOMAS J
sold
700 shares of
NET
at $329.373
$231KSep 17 · filed Sep 21Details
  • SEIFERT THOMAS Jsold1,196 shares ofNETat $331.59$397KSep 17 · filed Sep 21Details
  • SEIFERT THOMAS Jsold1,604 shares ofNETat $332.5$533KSep 17 · filed Sep 21Details
  • SEIFERT THOMAS Jsold2,632 shares ofNETat $333.617$878KSep 17 · filed Sep 21Details
  • SEIFERT THOMAS Jsold1,868 shares ofNETat $334.591$625KSep 17 · filed Sep 21Details
  • SEIFERT THOMAS Jsold600 shares ofNETat $335.32$201KSep 17 · filed Sep 21Details
  • SEIFERT THOMAS Jexercised10,000 shares ofNETat $0Sep 17 · filed Sep 21Details
  • SEIFERT THOMAS Jtax-withheld2,944 shares ofNETat $327.23$963KSep 15Details
  • SEIFERT THOMAS Jtraded10,000 shares ofNETAug 17 · filed Aug 19Details
  • SEIFERT THOMAS Jsold900 shares ofNETat $305.249$275KAug 17 · filed Aug 19Details
  • SEIFERT THOMAS Jsold2,944 shares ofNETat $306.243$902KAug 17 · filed Aug 19Details
  • SEIFERT THOMAS Jsold2,456 shares ofNETat $307.294$755KAug 17 · filed Aug 19Details
  • SEIFERT THOMAS Jsold3,100 shares ofNETat $308.23$956KAug 17 · filed Aug 19Details
  • SEIFERT THOMAS Jsold300 shares ofNETat $309.07$93KAug 17 · filed Aug 19Details
  • SEIFERT THOMAS Jsold200 shares ofNETat $312.32$62KAug 17 · filed Aug 19Details
  • SEIFERT THOMAS Jsold100 shares ofNETat $314.61$31KAug 17 · filed Aug 19Details
  • SEIFERT THOMAS Jexercised10,000 shares ofNETat $0Aug 17 · filed Aug 19Details
  • View all 166 trades →