Quantum Corp /De/ (QMCO) Institutional Ownership

Institutions by Trading Activity

Ownership Statistics

1,771,885Shares Outstanding

4,473,209Shares held by institutions

$25,094,702Value of institutional holdings

1,047.22%Institutional ownership %

1.93%Shares Changed QoQ

70No. of institutional investors

Shares Owned by Institutions

Shares Purchased/Sold by Institutions

Ownership Summary

Quantum Corp /De/ (NASDAQ:QMCO) currently has 38 active institutional owners and shareholders as of today (December 2025), that have filed 13F forms with the Securities Exchange Commission (SEC).

The percentage of Quantum owned by institutions changed from 6.5% in September 2025 to 15.3% in December 2025, marking a slight up trend.
Institutional share ownership changed by 132.49% QoQ, while the number of institutional owners saw a decrease of 17.39% YoY.
During the quarter, 30 institutions bought more Quantum shares, 6 sold shares, and 2 of the 38 total investors held their position steady.
The total number of shares held by institutions in Quantum increased to 1.97Mn as of December 2025, a net change of up by 1.12Mn shares quarter on quarter, and up 644.91K shares year over year.
The top institutional stake in Quantum as of December 31, 2025 belongs to VANGUARD GROUP INC, which owns 625.54K shares, or 4.86% of the company.
Among the most significant buyers of Quantum during December 2025 were Portolan Capital Management, LLC (477.21K), VANGUARD GROUP INC (321.94K), GEODE CAPITAL MANAGEMENT, LLC (77.44K), STATE STREET CORP (63.37K), BlackRock, Inc. (58.41K).
Leading sellers of Quantum stock in December 2025 included ROYAL BANK OF CANADA (21.88K), AlphaQuest LLC (6.15K), SBI Securities Co., Ltd. (3.54K), BNP PARIBAS FINANCIAL MARKETS (2.44K), Farther Finance Advisors, LLC (300).
The top 10 institutional holders of Quantum for the quarter ending December 2025 included VANGUARD GROUP INC (625.54K), Portolan Capital Management, LLC (477.21K), BlackRock, Inc. (220.75K), UBS Group AG (165.84K), GEODE CAPITAL MANAGEMENT, LLC (156.87K), STATE STREET CORP (90.71K), AlphaQuest LLC (29.39K), NORTHERN TRUST CORP (28.76K), FLAGSHIP HARBOR ADVISORS, LLC (26.59K), MARSHALL WACE, LLP (21.74K).

38 Institutional Holders

4,473,209 Total Shares Held

Rows:

Download Data

Owner Name	Date	Shares Held	Change (QoQ)	Change (%)	Value (USD)
VANGUARD GROUP INC	31 Dec, 2025	625,538	321,941	106.04%	$4,034,720.00
Portolan Capital Management, LLC	31 Dec, 2025	477,214	477,214	0.00%	$3,078,030.00
BlackRock, Inc.	31 Dec, 2025	220,746	58,408	35.98%	$1,423,812.00
UBS Group AG	31 Dec, 2025	165,838	3,233	1.99%	$1,069,655.00
GEODE CAPITAL MANAGEMENT, LLC	31 Dec, 2025	156,871	77,444	97.50%	$1,011,968.00
STATE STREET CORP	31 Dec, 2025	90,714	63,367	231.71%	$585,105.00
AlphaQuest LLC	31 Dec, 2025	29,386	-6,150	-17.31%	$189,540.00
NORTHERN TRUST CORP	31 Dec, 2025	28,762	17,075	146.10%	$185,515.00
FLAGSHIP HARBOR ADVISORS, LLC	31 Dec, 2025	26,585	3,875	17.06%	$171,475.00
MARSHALL WACE, LLP	31 Dec, 2025	21,740	21,740	0.00%	$140,223.00
BANK OF AMERICA CORP /DE/	31 Dec, 2025	20,535	17,639	609.08%	$132,450.00
LPL Financial LLC	31 Dec, 2025	18,364	18,364	0.00%	$118,448.00
Engineers Gate Manager LP	31 Dec, 2025	16,407	16,407	0.00%	$105,825.00
BARCLAYS PLC	31 Dec, 2025	14,197	13,742	3,020.22%	$91,571.00
CITIGROUP INC	31 Dec, 2025	12,828	12,828	0.00%	$82,741.00
XTX Topco Ltd	31 Dec, 2025	11,948	11,948	0.00%	$77,065.00
MILLENNIUM MANAGEMENT LLC	31 Dec, 2025	11,244	11,244	0.00%	$72,524.00
MORGAN STANLEY	31 Dec, 2025	4,313	957	28.52%	$27,819.00
NBC SECURITIES, INC.	31 Dec, 2025	4,000	4,000	0.00%	$25,800.00
WELLS FARGO & COMPANY/MN	31 Dec, 2025	3,525	3,285	1,368.75%	$22,736.00

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