Quantum (QMCO) Held by Superinvestors

QUANTUM CORP (QMCO) is currently held by 2 superinvestors tracked by InsiderSet, with a combined reported market value of approximately $23.83M based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026.

Oaktree Capital Management is currently the largest disclosed institutional shareholder of QMCO tracked by InsiderSet, reporting ownership valued at approximately $22.13M in its June 30, 2026 SEC Form 13F filing. Based on current market prices and the latest disclosed share count, the position is now estimated to be worth approximately $35.45M, representing an estimated gain of +60.18% since the filing period.

The top 10 institutional shareholders tracked on this page collectively account for approximately 100% of the total disclosed QMCO value among the investors covered in this analysis. Major shareholders include Oaktree Capital Management, Renaissance Technologies LLC, and several other long-term asset managers with concentrated positions in QUANTUM CORP (QMCO).

This page ranks the largest institutional QMCO shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.

NameInvestor/ManagerPortfolio %QuantityReported BalanceCurrent Estimated ValueGain/loss Since FilingEstimated Portfolio Performance
Oaktree Capital ManagementHoward Marks0.42%2,011,678$22,128,458$35,445,766+$13,317,308+60.18%
Renaissance Technologies LLCJim Simons0.00%154,516$1,699,676$2,722,572+$1,022,896+60.18%
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Frequently asked questions about QMCO

  • Who are the largest superinvestors holding QMCO?

    The largest superinvestors holding QMCO in the latest SEC Form 13F filings include Oaktree Capital Management and Renaissance Technologies LLC. InsiderSet ranks these superinvestors by their latest reported QMCO position.

  • What does the QMCO superinvestors page include?

    This page tracks QMCO positions reported by a curated group of notable institutional investors and fund managers through SEC Form 13F. QUANTUM CORP (QMCO) on this page reflects disclosed 13F holdings among those superinvestors, not every institutional shareholder of the stock.

  • How many superinvestors hold QMCO?

    InsiderSet currently tracks 2 superinvestors reporting QMCO holdings in the latest available 13F data. This is the curated set on this page, not the total number of institutions that own QMCO.

  • How much QMCO stock do superinvestors hold?

    Superinvestors tracked by InsiderSet disclosed approximately $23.83M in QMCO holdings for Q2 2026. This figure is reported 13F value as of the filing period, not necessarily today's market value, and it covers the curated superinvestors on this page rather than every institutional filer.

  • When were QMCO superinvestor holdings last updated?

    The latest QMCO superinvestor holdings on InsiderSet are based on SEC Form 13F filings for the quarter ended June 30, 2026. Form 13F filings are generally reported after the quarter ends, so the holdings shown represent the latest publicly disclosed positions rather than real-time holdings.

  • Are superinvestor QMCO holdings real-time?

    No. Form 13F data is not real-time. It represents positions reported by these superinvestors as of the end of the reporting quarter. A superinvestor may have changed its QMCO position after the reporting date.

  • Are superinvestors buying or selling QMCO?

    Buying and selling can be analyzed by comparing QMCO positions across consecutive 13F reporting periods. InsiderSet's QMCO Ownership Changes page shows institutions that increased, reduced, initiated, or exited positions based on reported 13F holdings. View QMCO ownership changes.

  • How have superinvestor QMCO holdings changed over time?

    InsiderSet tracks QMCO holdings among these superinvestors across multiple 13F reporting periods, so holder counts, reported value, and reported shares can be compared over time.