Atrium Therapeutics RNA Institutional Ownership

Updated Oct 10, 2026

Atrium Therapeutics, Inc. (NASDAQ:RNA) was reported as a holding by 155 institutional investors in 13F filings for the quarter ended June 30, 2026.

• Collectively, these holders controlled 83.49% of Atrium Therapeutics' outstanding shares in Q2 2026, down from 86.26% in Q1 2026.
• Total shares held in Atrium Therapeutics fell 3.21% versus Q1 2026.
• Of these 155 holders, 87 added to their positions, 35 reduced their stakes and 33 left their positions unchanged.
• Altogether, institutional holders owned 14.28Mn RNA shares at the end of Q2 2026, down 473.45K from the prior quarter.
• Sessa Capital IM, L.P. held the largest position in RNA at 1.5Mn shares as of June 30, 2026, or 8.77% of shares outstanding.
• Among holders that already owned Atrium Therapeutics, the biggest buyers in Q2 2026 were Sessa Capital IM, L.P. (+948.61K shares), BlackRock, Inc. (+242.19K shares), Two Sigma Investments, LP (+166.92K shares), Vanguard Capital Management LLC (+103.96K shares) and Jane Street Group, LLC (+89.86K shares).
• The biggest cuts to RNA positions during Q2 2026 came from Vanguard Portfolio Management LLC (-243.17K shares), Balyasny Asset Management L.P. (-129.24K shares), Morgan Stanley (-123.09K shares), Squarepoint Ops LLC (-84.72K shares) and Adage Capital Partners GP, L.L.C. (-83.58K shares).
• Business Quant data shows the 10 biggest positions in Atrium Therapeutics as of Q2 2026 were held by Sessa Capital IM, L.P. (1.5Mn shares), T. Rowe Price Associates Inc (1.47Mn shares), BlackRock, Inc. (1.45Mn shares), Vanguard Capital Management LLC (730.83K shares), CRCM LP (583.25K shares), TIG Advisors, LLC (561.53K shares), Geode Capital Management, LLC (386.93K shares), Two Sigma Investments, LP (345.48K shares), Goldman Sachs Group Inc (310.34K shares) and 683 Capital Management, LLC (300K shares).