QMCO Quantum Corp.

NASDAQ
$16.77

Quantum Corp. (QMCO) Institutional Ownership

What the institutions did with QMCO last quarter, from their 13F filings. Counting managers rather than shares is the point: a single index fund adding to a position tells you far less than four hundred separate managers all deciding to. Positions as reported for the quarter ended September 30, 2026.

Managers compared
16
filed both this quarter and last
Managers holding
16
+11 on the quarter
Buyers
12
11 opened new
Sellers
2
0 sold out entirely
Buyer share
85.7%
of managers who traded it
Breadth
+71.4
net buyers, as a share of those trading

Every manager below opens. Subscribers can see any firm's whole portfolio — every position, its weight, and what they bought, trimmed and exited last quarter.

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Ownership map

Each block is one manager, sized by shares held and colored by how much they moved the position last quarter. Green added, red cut, grey stood pat.

Cut Unchanged Added Color saturates at ±50%.

Largest holders

Manager Shares % of reported
Two Seas Capital LP 1.5M 95.8%
Y-Intercept (Hong Kong) Ltd 21.9K 1.4%
Cambridge Investment Research Advisors, Inc. 14.1K 0.9%
FLAGSHIP HARBOR ADVISORS, LLC 11.0K 0.7%
Calamos Advisors LLC 6.8K 0.4%
TRUE Private Wealth Advisors 6.6K 0.4%
State of Alaska, Department of Revenue 1.9K 0.1%
SBI Securities Co., Ltd. 1.3K 0.1%
SIGNATUREFD, LLC 696 0.0%
Carolina Wealth Advisors, LLC 416 0.0%
CITIGROUP INC 208 0.0%
Caitong International Asset Management Co., Ltd 121 0.0%
BLUE BELL PRIVATE WEALTH MANAGEMENT, LLC 34 0.0%
GK Wealth Management LLC 13 0.0%
Cassaday & Co Wealth Management LLC 7 0.0%
Farther Finance Advisors, LLC 4 0.0%

Largest changes

Manager Action Previous Current Change
Two Seas Capital LP Reduced 2.5M 1.5M -997.5K
Y-Intercept (Hong Kong) Ltd New 0 21.9K +21.9K
CITIGROUP INC Reduced 14.4K 208 -14.2K
Cambridge Investment Research Advisors, Inc. New 0 14.1K +14.1K
Calamos Advisors LLC New 0 6.8K +6.8K
TRUE Private Wealth Advisors New 0 6.6K +6.6K
State of Alaska, Department of Revenue New 0 1.9K +1.9K
SIGNATUREFD, LLC New 0 696 +696
Carolina Wealth Advisors, LLC New 0 416 +416
SBI Securities Co., Ltd. Increased 1.1K 1.3K +254
Caitong International Asset Management Co., Ltd New 0 121 +121
BLUE BELL PRIVATE WEALTH MANAGEMENT, LLC New 0 34 +34
GK Wealth Management LLC New 0 13 +13
Cassaday & Co Wealth Management LLC New 0 7 +7

13F filings are due 45 days after quarter end and cover long positions in U.S.-listed equities only, so this is a lagged and partial picture: shorts, bonds and foreign listings never appear. Options positions are excluded here rather than folded into the share counts. Political ownership is coming.