Vault-13

QUANTUM CORP QMCO

COM · Common Stock · CUSIP 747906600

60 institutional holders +23 vs Q1 2026
14,378,63214.4m shares reported held*
36.5% of all shares outstanding*
$157.3mreported value*
31 new 18 added 6 reduced 8 sold out net bought ≈ $141.8m (+12.9m 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: 39.4m as of 2026-06-24, 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 ≈ $10.94. Options: 8 managers hold calls ($6.5m notional), 4 hold puts ($992.2k).

Trends to Q2 2026

Institutional holders

Managers reporting a position, each quarter

0204060Q3 24: 26Q4 24: 46Q1 25: 30Q2 25: 36Q3 25: 29Q4 25: 40Q1 26: 37Q2 26: 6060Q3 24Q1 25Q3 25Q1 26Q2 26
Numbers
QuarterHolders
Q3 202426
Q4 202446
Q1 202530
Q2 202536
Q3 202529
Q4 202540
Q1 202637
Q2 202660

Buyers vs sellers

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

Bought or addedCut or sold out
50050Q4 24: 30 bought or addedQ4 24: 12 cut or sold outQ4 24Q1 25: 20 bought or addedQ1 25: 26 cut or sold outQ2 25: 22 bought or addedQ2 25: 15 cut or sold outQ2 25Q3 25: 16 bought or addedQ3 25: 14 cut or sold outQ4 25: 29 bought or addedQ4 25: 14 cut or sold outQ4 25Q1 26: 16 bought or addedQ1 26: 22 cut or sold outQ2 26: 49 bought or addedQ2 26: 14 cut or sold outQ2 26
Numbers
QuarterBought or addedCut or sold out
Q4 20243012
Q1 20252026
Q2 20252215
Q3 20251614
Q4 20252914
Q1 20261622
Q2 20264914

Calls vs puts

Options held, notional value, last 4 quarters. P/C = puts ÷ calls

CallsPuts
$0$2m$4m$6m$8mQ3 25 calls: $0Q3 25 puts: $0Q3 25P/C —Q4 25 calls: $0Q4 25 puts: $0Q4 25P/C —Q1 26 calls: $0Q1 26 puts: $0Q1 26P/C —Q2 26 calls: $6.5mQ2 26 puts: $992.2kQ2 26P/C 0.15
Numbers
QuarterCallsPutsP/C
Q3 2025$0$0—
Q4 2025$0$0—
Q1 2026$0$0—
Q2 2026$6.5m$992.2k0.15

Biggest buyers

Alyeska Investment Group, L.P. New +2,653,928+2.7m
Two Seas Capital LP New +2,488,535+2.5m
OAKTREE CAPITAL MANAGEMENT LP New +2,011,678+2.0m
NEUBERGER BERMAN GROUP LLC New +1,163,315+1.2m
ASHFORD CAPITAL MANAGEMENT INC New +1,039,200+1.0m
Portolan Capital Management, LLC New +1,020,120+1.0m
MARSHALL WACE, LLP Added +675,547+675.5k
Manatuck Hill Partners, LLC New +350,000+350.0k
Cinctive Capital Management LP New +182,769+182.8k
RENAISSANCE TECHNOLOGIES LLC New +154,516+154.5k

Biggest sellers

UBS Group AG Reduced -52,962-53.0k
LPL Financial LLC Sold out -24,598-24.6k
R Squared Ltd Sold out -12,245-12.2k
BARCLAYS PLC Reduced -11,988-12.0k
XTX Topco Ltd Sold out -11,321-11.3k
FLAGSHIP HARBOR ADVISORS, LLC Reduced -6,181-6.2k
HOLLENCREST CAPITAL MANAGEMENT Reduced -1,990-2.0k
SBI Securities Co., Ltd. Reduced -934-934
OSAIC HOLDINGS, INC. Reduced -480-480
NATIONAL BANK OF CANADA /FI/ Sold out -100-100

Biggest calls

JANE STREET GROUP, LLC New $1.9m170.6k shares
CITADEL ADVISORS LLC New $1.3m116.2k shares
SUSQUEHANNA INTERNATIONAL GROUP, LLP New $1.1m104.0k shares
SONA ASSET MANAGEMENT (US) LLC New $1.1m100.1k shares
SIMPLEX TRADING, LLC New $764.5k69.5k shares
IMC-Chicago, LLC New $143.0k13.0k shares
TUDOR INVESTMENT CORP ET AL New $114.4k10.4k shares
GROUP ONE TRADING LLC New $100.1k9.1k shares

Biggest puts

JANE STREET GROUP, LLC New $416.9k37.9k shares
SUSQUEHANNA INTERNATIONAL GROUP, LLP New $289.3k26.3k shares
CITADEL ADVISORS LLC New $226.6k20.6k shares
SIMPLEX TRADING, LLC New $59.4k5.4k shares

Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.

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 since 1 Apr 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
505Q4 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 26Q2 26: 0 buyingQ2 26: 1 sellingQ3 26: 0 buyingQ3 26: 3 sellingQ3 26
Numbers
QuarterBuyingBoughtSellingSoldSold under a plan
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——
Q2 20260—1$593—
Q3 20260—3$84.1k—
DateInsiderTradeSharesPrice ValueTheir holding
2026-08-03 Craythorne Anthony Chief Revenue Officer Sold 1,478 $10.73 $15.9k1.5k shares -10%
2026-07-02 Meyrath Hugues President & CEO, director Sold 6,232 $10.51 $65.5k6.2k shares -5%
2026-07-02 Nash Laura A. Chief Accounting Officer Sold 260 $10.51 $2.7k260 shares -2%
2026-04-02 Nash Laura A. Chief Accounting Officer Sold 109 $5.44 $593109 shares -1%

Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).

Holders, Q2 2026

#ManagerLocationShares Value% of their portfolioChangeShares change
1 Alyeska Investment Group, L.P. 0.08% of their portfolio CHICAGO, IL 2,653,9282.7m $29.2m $29.2m 0.08% New
2 Two Seas Capital LP 1.04% of their portfolio RYE, NY 2,488,5352.5m $27.4m $27.4m 1.04% New
3 OAKTREE CAPITAL MANAGEMENT LP 0.42% of their portfolio LOS ANGELES, CA 2,011,6782.0m $22.1m $22.1m 0.42% New
4 NEUBERGER BERMAN GROUP LLC 0.01% of their portfolio NEW YORK, NY 1,163,3151.2m $12.8m $12.8m 0.01% New
5 ASHFORD CAPITAL MANAGEMENT INC 1.13% of their portfolio WILMINGTON, DE 1,039,2001.0m $10.6m $10.6m 1.13% New
6 Portolan Capital Management, LLC 0.42% of their portfolio BOSTON, MA 1,020,1201.0m $11.2m $11.2m 0.42% New
7 MARSHALL WACE, LLP 0.01% of their portfolio LONDON, X0 713,075713.1k $7.8m $7.8m 0.01% Added +675.5k +675,547
8 VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio MALVERN, PA 605,541605.5k $6.7m $6.7m 0.00% Added +66.3k +66,266
9 Manatuck Hill Partners, LLC 1.28% of their portfolio WESTPORT, CT 350,000350.0k $3.9m $3.9m 1.28% New
10 BlackRock, Inc. 0.00% of their portfolio New York, NY 273,030273.0k $3.0m $3.0m 0.00% Added +55.5k +55,498
11 Cinctive Capital Management LP 0.08% of their portfolio New York, NY 182,769182.8k $2.0m $2.0m 0.08% New
12 BANK OF AMERICA CORP /DE/ 0.00% of their portfolio CHARLOTTE, NC 170,130170.1k $1.9m $1.9m 0.00% Added +149.6k +149,645
13 GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio BOSTON, MA 164,600164.6k $1.8m $1.8m 0.00% Added +5.4k +5,421
14 RENAISSANCE TECHNOLOGIES LLC 0.00% of their portfolio NEW YORK, NY 154,516154.5k $1.7m $1.7m 0.00% New
15 SONA ASSET MANAGEMENT (US) LLC 0.06% of their portfolio NEW YORK, NY 150,000150.0k $1.6m $1.6m 0.06% Added +79.9k +79,908
16 Walleye Capital LLC 0.01% of their portfolio NEW YORK, NY 120,044120.0k $1.3m $1.3m 0.01% New
17 RAYMOND JAMES FINANCIAL INC 0.00% of their portfolio ST. PETERSBURG, FL 103,836103.8k $1.1m $1.1m 0.00% New
18 Centiva Capital, LP 0.04% of their portfolio New York, NY 100,000100.0k $1.1m $1.1m 0.04% New
19 KKM Financial LLC 0.13% of their portfolio CHICAGO, IL 90,27490.3k $960.5k $960.5k 0.13% New
20 VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio MALVERN, PA 89,12589.1k $980.4k $980.4k 0.00% Added +8.9k +8,862
21 Qube Research & Technologies Ltd 0.00% of their portfolio LONDON, X0 80,97781.0k $890.7k $890.7k 0.00% New
22 STATE STREET CORP 0.00% of their portfolio BOSTON, MA 75,91475.9k $835.1k $835.1k 0.00% Added +3.1k +3,100
23 SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.00% of their portfolio BALA CYNWYD, PA 69,77569.8k $767.5k $767.5k 0.00% New
24 Man Group plc 0.00% of their portfolio LONDON, X0 68,59368.6k $754.5k $754.5k 0.00% New
25 Informed Momentum Co LLC 0.06% of their portfolio SOLANA BEACH, CA 64,85764.9k $713.4k $713.4k 0.06% New
26 UBS Group AG 0.00% of their portfolio ZURICH, V8 46,10646.1k $507.2k $507.2k 0.00% Reduced -53.0k -52,962
27 SEI INVESTMENTS CO 0.00% of their portfolio OAKS, PA 38,73938.7k $426.1k $426.1k 0.00% New
28 SUSQUEHANNA FUNDAMENTAL INVESTMENTS, LLC 0.01% of their portfolio BALA CYNWYD, PA 34,60134.6k $380.6k $380.6k 0.01% New
29 Squarepoint Ops LLC 0.00% of their portfolio NEW YORK, NY 33,81733.8k $372.0k $372.0k 0.00% New
30 NORTHERN TRUST CORP 0.00% of their portfolio CHICAGO, IL 33,22033.2k $365.4k $365.4k 0.00% Added +4.5k +4,458
31 PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio BALTIMORE, MD 25,06925.1k $276.0k $276.0k 0.00% Added +3.3k +3,268
32 MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio NEW YORK, NY 21,75521.8k $239.3k $239.3k 0.00% New
33 GOLDMAN SACHS GROUP INC 0.00% of their portfolio NEW YORK, NY 19,15319.2k $210.7k $210.7k 0.00% New
34 BRIDGEWAY CAPITAL MANAGEMENT, LLC 0.00% of their portfolio HOUSTON, TX 16,24016.2k $178.6k $178.6k 0.00% Unchanged
35 MORGAN STANLEY 0.00% of their portfolio NEW YORK, NY 15,49215.5k $170.4k $170.4k 0.00% Added +313 +313
36 CITIGROUP INC 0.00% of their portfolio NEW YORK, NY 14,42614.4k $158.7k $158.7k 0.00% New
37 Kovack Advisors, Inc. 0.01% of their portfolio FT. LAUDERDALE, FL 13,43013.4k $146.8k $146.8k 0.01% Added +950 +950
38 Schonfeld Strategic Advisors LLC 0.00% of their portfolio NEW YORK, NY 12,05512.1k $132.6k $132.6k 0.00% New
39 WELLS FARGO & COMPANY/MN 0.00% of their portfolio SAN FRANCISCO, CA 11,30011.3k $124.3k $124.3k 0.00% Added +7.2k +7,175
40 FLAGSHIP HARBOR ADVISORS, LLC 0.00% of their portfolio BOSTON, MA 11,00411.0k $121.0k $121.0k 0.00% Reduced -6.2k -6,181
41 Invesco Ltd. 0.00% of their portfolio ATLANTA, GA 10,83910.8k $119.2k $119.2k 0.00% New
42 Vanguard Global Advisers, LLC 0.00% of their portfolio MALVERN, PA 6,0006.0k $66.0k $66.0k 0.00% Unchanged
43 JPMORGAN CHASE & CO 0.00% of their portfolio NEW YORK, NY 3,6803.7k $43.6k $43.6k 0.00% Added +3.7k +3,672
44 JONES FINANCIAL COMPANIES LLLP 0.00% of their portfolio DES PERES, MO 1,5801.6k $18.4k $18.4k 0.00% Added +113 +113
45 BNP PARIBAS FINANCIAL MARKETS 0.00% of their portfolio PARIS, I0 1,1871.2k $13.1k $13.1k 0.00% Added +926 +926
46 FEDERATED HERMES, INC. 0.00% of their portfolio PITTSBURGH, PA 1,1581.2k $12.7k $12.7k 0.00% Added +323 +323
47 SBI Securities Co., Ltd. 0.00% of their portfolio TOKYO, M0 1,0701.1k $11.8k $11.8k 0.00% Reduced -934 -934
48 ROYAL BANK OF CANADA 0.00% of their portfolio TORONTO, A6 765765 $8.0k $8.0k 0.00% Added +637 +637
49 Tower Research Capital LLC (TRC) 0.00% of their portfolio NEW YORK, NY 655655 $7.2k $7.2k 0.00% New
50 OSAIC HOLDINGS, INC. 0.00% of their portfolio SCOTTSDALE, AZ 485485 $5.3k $5.3k 0.00% Reduced -480 -480
51 BARCLAYS PLC 0.00% of their portfolio LONDON, X0 455455 $5.0k $5.0k 0.00% Reduced -12.0k -11,988
52 HARBOUR INVESTMENTS, INC. 0.00% of their portfolio MADISON, WI 183183 $2.0k $2.0k 0.00% New
53 FMR LLC 0.00% of their portfolio BOSTON, MA 106106 $1.2k $1.2k 0.00% New
54 EFG International AG 0.00% of their portfolio Zurich, V8 100100 $1.1k $1.1k 0.00% Unchanged
55 Global Retirement Partners, LLC 0.00% of their portfolio San Rafael, CA 6565 $715 $715 0.00% First filing
56 Continuum Advisory, LLC 0.00% of their portfolio EAGLE, ID 3434 $374 $374 0.00% New
57 Quarry LP 0.00% of their portfolio NEW YORK, NY 1717 $187 $187 0.00% New
58 HOLLENCREST CAPITAL MANAGEMENT 0.00% of their portfolio NEWPORT BEACH, CA 1010 $110 $110 0.00% Reduced -2.0k -1,990
59 Farther Finance Advisors, LLC 0.00% of their portfolio SAN FRANCISCO, CA 44 $44 $44 0.00% Unchanged
60 NewEdge Advisors, LLC 0.00% of their portfolio NEW ORLEANS, LA 00 $0 $0 0.00% New