Perimeter Solutions PRM Insider Ownership

Updated Oct 10, 2026

In the last 12 months, insiders at Perimeter Solutions made open-market sales of $239.62 million (7.27Mn shares) and bought no shares on the open market.

• A count shows 6 insiders selling PRM stock on the open market over the past 12 months and none buying.
• Windacre Partnership LLC (10% owner) led open-market sales of Perimeter Solutions stock over the past 12 months with $195.61 million (5.71Mn shares), most recently on June 30, 2026.
• Outside the open market, Perimeter Solutions insiders received 7.8Mn shares in stock awards, acquired 687.5K shares through option exercises and conversions and gave away 7Mn shares as gifts over the past 12 months.
• Business Quant data shows Perimeter Solutions insiders holding 52.2Mn shares in total in their latest Form 4 filings, down 0.19% from 52.3Mn shares at the end of Q2 2026.
• By type of ownership, PRM insiders hold 97.08% of their shares directly (50.67Mn shares) and 2.92% indirectly (1.52Mn shares).
• Per Business Quant, 12 insiders of PRM hold shares, counting officers, directors and 10% owners who have filed a Form 4 in the past two years.
• PRM's largest insider holders by reported holdings are Windacre Partnership Master Fund, LP (10% owner, 21.85Mn shares), Windacre Partnership LLC (10% owner, 16.15Mn shares) and William N. Thorndike Jr. (Director, 8.54Mn shares).
• Windacre Partnership Master Fund, LP alone accounts for 41.87% of the shares held by Perimeter Solutions insiders.
• In their Q2 2026 13F filings, institutions reported holding 83.31% of Perimeter Solutions' outstanding shares.
• In the past year, 14 insiders of Perimeter Solutions submitted 31 Form 4 filings reporting trades, awards or other transactions.
• These insider figures for Perimeter Solutions are based on Form 4 filings through July 13, 2026.