Mark Lowham, TTR SIR – Swanepoel Power 200 | Real Estate Almanac
Mark Lowham
Mark Lowham
CEO and Managing Partner
TTR SIR
Mc Lean, VA
129
SP 200 Ranking
Last updated: February 06, 2026
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Mark Lowham
CEO and Managing Partner, TTR SIR
Mc Lean, VA
129
SP 200 Ranking
Last updated: February 06, 2026
Share this profile:
Executive Biography
Lowham was recently named chairman of the Washington, DC-based TTR Sotheby’s International Realty. Lowham is a second-generation real estate professional who made his first sale at 19. In his previous role as the firm’s CEO — a position he held for 15 years — Lowham oversaw about 650 agents who do approximately $4.5 billion in annual sales. In 2025, TTR SIR acquired HRLS Partners, a move that increased the company’s DC-area office count to 13.