Quantum Corp /De/ (QMCO) Institutional Ownership

Ownership Summary

According to SEC filings for the period ending September 2025, Quantum Corp /De/ (NASDAQ:QMCO) is held by 29 institutional firms.

• Institutional ownership in Quantum edged up to 12.2% in September 2025, compared to 9.6% in June 2025.
• Quarterly data indicates a 32.19% shift in institutional share volume, and the annual owner count reflects an increase of 11.54%.
• During the quarter, 16 institutions bought more Quantum shares, 4 sold shares, and 9 of the 29 total investors held their position steady.
• The total number of shares held by institutions in Quantum increased to 865.12K as of September 2025, a net change of up by 210.66K shares quarter on quarter, and down 1.89Mn shares year over year.
• The top institutional stake in Quantum as of September 30, 2025 belongs to VANGUARD GROUP INC, which owns 303.60K shares, or 4.28% of the company.
• Among the most significant buyers of Quantum during September 2025 were UBS Group AG (102.38K), VANGUARD GROUP INC (46.92K), AlphaQuest LLC (30.83K), FLAGSHIP HARBOR ADVISORS, LLC (22.71K), BlackRock, Inc. (21.03K).
• Leading sellers of Quantum stock in September 2025 included MORGAN STANLEY (42.38K), WELLS FARGO & COMPANY/MN (5.08K), FNY Investment Advisers, LLC (394), Tower Research Capital LLC (TRC) (295).
• The top 10 institutional holders of Quantum for the quarter ending September 2025 included VANGUARD GROUP INC (303.60K), UBS Group AG (162.60K), BlackRock, Inc. (162.34K), GEODE CAPITAL MANAGEMENT, LLC (79.43K), AlphaQuest LLC (35.54K), STATE STREET CORP (27.35K), ROYAL BANK OF CANADA (22.71K), FLAGSHIP HARBOR ADVISORS, LLC (22.71K), NORTHERN TRUST CORP (11.69K), Riverview Capital Advisers, LLC (10.00K).