Vault-13

QUANTUM CORP QMCO

COM · Common Stock · CUSIP 747906600

37 institutional holders -3 vs Q4 2025
1,610,7251.6m shares reported held*
11.0% of all shares outstanding*
$7.7mreported value*
7 new 9 added 11 reduced 11 sold out net sold ≈ $2.1m (-444.3k shares)

* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once. Holder counts are more reliable. Shares outstanding: 14.6m as of 2026-02-12, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $4.75.

Trends to Q1 2026

Institutional holders

Managers reporting a position, each quarter

0204060Q3 24: 26Q4 24: 46Q1 25: 30Q2 25: 36Q3 25: 29Q4 25: 40Q1 26: 3737Q3 24Q1 25Q3 25Q1 26
Numbers
QuarterHolders
Q3 202426
Q4 202446
Q1 202530
Q2 202536
Q3 202529
Q4 202540
Q1 202637

Buyers vs sellers

Managers adding to or starting a position, vs cutting or selling out

Bought or addedCut or sold out
40040Q4 24: 30 bought or addedQ4 24: 12 cut or sold outQ4 24Q1 25: 20 bought or addedQ1 25: 26 cut or sold outQ1 25Q2 25: 22 bought or addedQ2 25: 15 cut or sold outQ2 25Q3 25: 16 bought or addedQ3 25: 14 cut or sold outQ3 25Q4 25: 29 bought or addedQ4 25: 14 cut or sold outQ4 25Q1 26: 16 bought or addedQ1 26: 22 cut or sold outQ1 26
Numbers
QuarterBought or addedCut or sold out
Q4 20243012
Q1 20252026
Q2 20252215
Q3 20251614
Q4 20252914
Q1 20261622

Biggest buyers

SONA ASSET MANAGEMENT (US) LLC New +70,092+70.1k
Cygnus Capital Advisors, LLC Added +54,663+54.7k
BRIDGEWAY CAPITAL MANAGEMENT, LLC New +16,240+16.2k
MARSHALL WACE, LLP Added +15,788+15.8k
Kovack Advisors, Inc. New +12,480+12.5k
R Squared Ltd New +12,245+12.2k
MORGAN STANLEY Added +10,866+10.9k
LPL Financial LLC Added +6,234+6.2k
PRICE T ROWE ASSOCIATES INC /MD/ Added +5,900+5.9k
GEODE CAPITAL MANAGEMENT, LLC Added +2,308+2.3k

Biggest sellers

Portolan Capital Management, LLC Sold out -477,214-477.2k
UBS Group AG Reduced -66,770-66.8k
AlphaQuest LLC Sold out -29,386-29.4k
STATE STREET CORP Reduced -17,900-17.9k
Engineers Gate Manager LP Sold out -16,407-16.4k
CITIGROUP INC Sold out -12,828-12.8k
MILLENNIUM MANAGEMENT LLC Sold out -11,244-11.2k
FLAGSHIP HARBOR ADVISORS, LLC Reduced -9,400-9.4k
LANARK FINANCIAL, INC. Sold out -4,000-4.0k
BlackRock, Inc. Reduced -3,214-3.2k

Major shareholders (over 5%)

Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.

HolderStakeChangeShares Last filed
Dialectic Technology SPV LLC 13D · may seek influence -1.4 pts · filed 2026-06-08
Stated purposeItem 4 of the Amended Statement is hereby amended by adding the following paragraphs to the end of Item 4: Entry into Conversion Agreement On June 4, 2026 (the "Closing"), the Company issued and sold to certain accredited investors in a private placement (the "Private Placement"), an aggregate of 10,615,712 shares of Common Stock. In order to facilitate, among other things, the Private Placement, Dialectic, as the sole beneficial owner of the Convertible Notes issued under the Indenture, agreed to voluntarily convert the Convertible Notes into Common Stock. Pursuant to a Conversion Agreement dated June 1, 2026 (the "Conversion Agreement"), by and among the Company, Dialectic and, solely with respect to Sections 7.1 and 7.3 and Articles III and X thereof, U.S. Bank Trust Company, Nationa… Full filing
40.0% -1.4 pts 16.9m≈ $185.8m 2026-06-08
Alyeska Investment Group, L.P. 13G · institution new · filed 2026-08-14 6.7% new 2.7m≈ $29.2m 2026-08-14
Two Seas Capital LP 13G · institution new · filed 2026-08-14 6.3% new 2.5m≈ $27.4m 2026-08-14
OAKTREE CAPITAL MANAGEMENT LP 13G · institution new · filed 2026-08-10 5.1% new 2.0m≈ $22.1m 2026-08-10

Insider purchases and sales in Q1 2026

Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.

Officers and directors buying vs selling

Number of people, by quarter (10% owners not included)

BuyingSelling
505Q2 24: 0 buyingQ2 24: 0 sellingQ3 24: 0 buyingQ3 24: 0 sellingQ3 24Q4 24: 0 buyingQ4 24: 5 sellingQ1 25: 0 buyingQ1 25: 4 sellingQ1 25Q2 25: 0 buyingQ2 25: 4 sellingQ3 25: 0 buyingQ3 25: 1 sellingQ3 25Q4 25: 0 buyingQ4 25: 2 sellingQ1 26: 0 buyingQ1 26: 0 sellingQ1 26
Numbers
QuarterBuyingBoughtSellingSoldSold under a plan
Q2 20240—0——
Q3 20240—0——
Q4 20240—5$35.3k—
Q1 20250—4$274.8k—
Q2 20250—4$40.7k—
Q3 20250—1$2.1k—
Q4 20250—2$40.1k—
Q1 20260—0——

None reported in Q1 2026.

Holders, Q1 2026

#ManagerLocationShares Value% of their portfolioChangeShares change
1 VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio MALVERN, PA 539,275539.3k $2.6m $2.6m 0.00% First filing
2 BlackRock, Inc. 0.00% of their portfolio New York, NY 217,532217.5k $1.0m $1.0m 0.00% Reduced -3.2k -3,214
3 GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio BOSTON, MA 159,179159.2k $756.5k $756.5k 0.00% Added +2.3k +2,308
4 Cygnus Capital Advisors, LLC 0.40% of their portfolio ATLANTA, GA 124,086124.1k $590.0k $590.0k 0.40% Added +54.7k +54,663
5 UBS Group AG 0.00% of their portfolio ZURICH, V8 99,06899.1k $470.6k $470.6k 0.00% Reduced -66.8k -66,770
6 VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio MALVERN, PA 80,26380.3k $381.2k $381.2k 0.00% First filing
7 STATE STREET CORP 0.00% of their portfolio BOSTON, MA 72,81472.8k $345.9k $345.9k 0.00% Reduced -17.9k -17,900
8 SONA ASSET MANAGEMENT (US) LLC 0.01% of their portfolio NEW YORK, NY 70,09270.1k $332.9k $332.9k 0.01% New
9 MARSHALL WACE, LLP 0.00% of their portfolio LONDON, X0 37,52837.5k $178.3k $178.3k 0.00% Added +15.8k +15,788
10 NORTHERN TRUST CORP 0.00% of their portfolio CHICAGO, IL 28,76228.8k $136.6k $136.6k 0.00% Unchanged
11 LPL Financial LLC 0.00% of their portfolio FORT MILL, SC 24,59824.6k $116.8k $116.8k 0.00% Added +6.2k +6,234
12 PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio BALTIMORE, MD 21,80121.8k $104.0k $104.0k 0.00% Added +5.9k +5,900
13 BANK OF AMERICA CORP /DE/ 0.00% of their portfolio CHARLOTTE, NC 20,48520.5k $97.3k $97.3k 0.00% Reduced -50 -50
14 FLAGSHIP HARBOR ADVISORS, LLC 0.00% of their portfolio BOSTON, MA 17,18517.2k $81.6k $81.6k 0.00% Reduced -9.4k -9,400
15 BRIDGEWAY CAPITAL MANAGEMENT, LLC 0.00% of their portfolio HOUSTON, TX 16,24016.2k $77.1k $77.1k 0.00% New
16 MORGAN STANLEY 0.00% of their portfolio NEW YORK, NY 15,17915.2k $72.1k $72.1k 0.00% Added +10.9k +10,866
17 Kovack Advisors, Inc. 0.00% of their portfolio FT. LAUDERDALE, FL 12,48012.5k $62.8k $62.8k 0.00% New
18 BARCLAYS PLC 0.00% of their portfolio LONDON, X0 12,44312.4k $59.1k $59.1k 0.00% Reduced -1.8k -1,754
19 R Squared Ltd 0.03% of their portfolio HONG KONG, K3 12,24512.2k $58.2k $58.2k 0.03% New
20 XTX Topco Ltd 0.00% of their portfolio LONDON, X0 11,32111.3k $53.8k $53.8k 0.00% Reduced -627 -627
21 Vanguard Global Advisers, LLC 0.00% of their portfolio MALVERN, PA 6,0006.0k $28.5k $28.5k 0.00% First filing
22 WELLS FARGO & COMPANY/MN 0.00% of their portfolio SAN FRANCISCO, CA 4,1254.1k $19.6k $19.6k 0.00% Added +600 +600
23 SBI Securities Co., Ltd. 0.00% of their portfolio TOKYO, M0 2,0042.0k $9.5k $9.5k 0.00% Reduced -421 -421
24 HOLLENCREST CAPITAL MANAGEMENT 0.00% of their portfolio NEWPORT BEACH, CA 2,0002.0k $9.5k $9.5k 0.00% New
25 JONES FINANCIAL COMPANIES LLLP 0.00% of their portfolio DES PERES, MO 1,4671.5k $6.9k $6.9k 0.00% Reduced -374 -374
26 OSAIC HOLDINGS, INC. 0.00% of their portfolio SCOTTSDALE, AZ 965965 $4.6k $4.6k 0.00% Added +217 +217
27 FEDERATED HERMES, INC. 0.00% of their portfolio PITTSBURGH, PA 835835 $4.0k $4.0k 0.00% Added +334 +334
28 BNP PARIBAS FINANCIAL MARKETS 0.00% of their portfolio PARIS, I0 261261 $1.2k $1.2k 0.00% Reduced -758 -758
29 ROYAL BANK OF CANADA 0.00% of their portfolio TORONTO, A6 128128 $1.0k $1.0k 0.00% Reduced -705 -705
30 NATIONAL BANK OF CANADA /FI/ 0.00% of their portfolio MONTREAL, A8 100100 $475 $475 0.00% Unchanged
31 EFG International AG 0.00% of their portfolio Zurich, V8 100100 $477 $477 0.00% Unchanged
32 Rialto Wealth Management, LLC 0.00% of their portfolio SYRACUSE, NY 8787 $414 $414 0.00% New
33 Lavaca Capital LLC 0.00% of their portfolio HOUSTON, TX 3939 $185 $185 0.00% New
34 Federation des caisses Desjardins du Quebec 0.00% of their portfolio LEVIS, A8 2525 $119 $119 0.00% Unchanged
35 JPMORGAN CHASE & CO 0.00% of their portfolio NEW YORK, NY 88 $34 $34 0.00% Unchanged
36 Farther Finance Advisors, LLC 0.00% of their portfolio SAN FRANCISCO, CA 44 $20 $20 0.00% Unchanged
37 Activest Wealth Management 0.00% of their portfolio AVENTURA, FL 11 $4 $4 0.00% Unchanged