Mark A. McCollum

Companies

• ONEOKBoard member Jan 27, 2026 to now¹
• SeadrillBoard member Jan 2, 2025 to now²
• Westlake CorporationBoard member May 21, 2018 to now³
• Marathon OilBoard member Dec 1, 2022 to Nov 22, 2024⁴
• Weatherford International plcBoard member Apr 25, 2017 to Dec 17, 2019⁵
• Weatherford International plcChief executive officer Apr 25, 2017 to Dec 17, 2019⁵
• Weatherford International plcPresident Apr 25, 2017 to Dec 17, 2019⁵
• Archrock, Inc.Board member Jun 1, 2009 to Apr 27, 2018⁶
• HalliburtonChief financial officer Dec 7, 2010 to Mar 1, 2017⁷
• HalliburtonSenior VP, Chief Acctg. Off. Aug 25, 2003 to Dec 9, 2016⁸
• KBR, Inc.Board member Nov 15, 2006 to Nov 15, 2006⁹

Holdings

Stock this person has reported owning, from the forms officers and directors file with the SEC. See the biggest insider stakes.

Shares held

• Halliburton HAL204,993 shares¹⁰$6.9M at $33.83Feb 27, 2017
• Westlake Corporation WLK11,824 shares¹¹$723.3K at $61.17Aug 8, 2026
• SSeadrill SDRL7,269 shares¹²$349.8K at $48.12May 14, 2026
• ONEOK OKE2,572 shares¹³$240.6K at $93.56May 20, 2026
• Marathon Oil MRO0 shares¹⁴Nov 22, 2024

As of each latest filing. The line shows shares held over time.

Recent filings

• Aug 8, 2026Exercised options 2,168 shares of Westlake Corporation¹¹
• May 20, 2026Granted 1,845 shares at $92.15 of ONEOK¹³
• May 14, 2026Exercised options 4,860 shares of Seadrill¹²
• Jan 23, 2026Granted 727 shares at $78.00 of ONEOK¹⁵
• Aug 9, 2025Exercised options 1,128 shares of Westlake Corporation¹⁶
• Apr 17, 2025Exercised options 2,409 shares of Seadrill¹⁷
• Nov 22, 2024Returned to company 8,130 shares of Marathon Oil¹⁴
• Nov 22, 2024Returned to company 8,169 shares of Marathon Oil¹⁴
• Aug 11, 2024Exercised options 1,136 shares of Westlake Corporation¹⁸
• Mar 1, 2024Granted 8,130 shares of Marathon Oil¹⁹
• Aug 12, 2023Exercised options 1,446 shares of Westlake Corporation²⁰
• Mar 1, 2023Granted 7,754 shares of Marathon Oil²¹
• Dec 1, 2022Granted 415 shares of Marathon Oil²²
• Aug 13, 2022Exercised options 1,763 shares of Westlake Corporation²³
• Mar 3, 2022Gift 3,000 shares of Westlake Corporation²⁴
• Feb 27, 2017Sold 44,100 shares at $53.30 of Halliburton¹⁰
• Feb 27, 2017Exercised options 44,100 shares at $33.50 of Halliburton¹⁰
• Feb 27, 2017Sold 33,200 shares at $53.30 of Halliburton¹⁰
• Feb 27, 2017Exercised options 33,200 shares at $35.57 of Halliburton¹⁰
• Feb 27, 2017Sold 12,000 shares at $53.30 of Halliburton¹⁰
• Feb 27, 2017Exercised options 12,000 shares at $36.90 of Halliburton¹⁰
• Dec 8, 2016Shares withheld for tax 2,711 shares at $54.02 of Halliburton²⁵
• Dec 7, 2016Shares withheld for tax 2,677 shares at $53.90 of Halliburton²⁶
• Dec 7, 2016Granted 18,400 shares at $53.54 of Halliburton²⁵
• Dec 6, 2016Shares withheld for tax 6,512 shares at $54.17 of Halliburton²⁶