Vault-13

MAMMOTH ENERGY SVCS INC TUSK

COM · Common Stock · CUSIP 56155L108

94 institutional holders +4 vs Q1 2026
25,833,55625.8m shares reported held*
53.7% of all shares outstanding*
$84.0mreported value*
28 new 33 added 23 reduced 23 sold out net sold ≈ $29.2m (-9.0m 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 ($791.6k this quarter). Holder counts are more reliable. Shares outstanding: 48.1m as of 2026-08-04, 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 ≈ $3.25. Options: 2 managers hold calls ($475.5k notional), 2 hold puts ($11.7k).

Trends to Q2 2026

Institutional holders

Managers reporting a position, each quarter

050100Q3 22: 58Q4 22: 81Q1 23: 78Q2 23: 73Q3 23: 76Q4 23: 68Q1 24: 68Q2 24: 68Q3 24: 65Q4 24: 68Q1 25: 67Q2 25: 67Q3 25: 77Q4 25: 72Q1 26: 90Q2 26: 9494Q3 22Q3 23Q3 24Q3 25Q2 26
Numbers
QuarterHolders
Q3 202258
Q4 202281
Q1 202378
Q2 202373
Q3 202376
Q4 202368
Q1 202468
Q2 202468
Q3 202465
Q4 202468
Q1 202567
Q2 202567
Q3 202577
Q4 202572
Q1 202690
Q2 202694

Buyers vs sellers

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

Bought or addedCut or sold out
1000100Q3 24: 32 bought or addedQ3 24: 24 cut or sold outQ4 24: 33 bought or addedQ4 24: 23 cut or sold outQ4 24Q1 25: 27 bought or addedQ1 25: 31 cut or sold outQ2 25: 36 bought or addedQ2 25: 23 cut or sold outQ2 25Q3 25: 33 bought or addedQ3 25: 34 cut or sold outQ4 25: 31 bought or addedQ4 25: 40 cut or sold outQ4 25Q1 26: 52 bought or addedQ1 26: 36 cut or sold outQ2 26: 61 bought or addedQ2 26: 46 cut or sold outQ2 26
Numbers
QuarterBought or addedCut or sold out
Q3 20243224
Q4 20243323
Q1 20252731
Q2 20253623
Q3 20253334
Q4 20253140
Q1 20265236
Q2 20266146

Calls vs puts

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

CallsPuts
$0$200k$400k$600kQ3 25 calls: $35.0kQ3 25 puts: $102.4kQ3 25P/C 2.93Q4 25 calls: $1.3kQ4 25 puts: $185Q4 25P/C 0.14Q1 26 calls: $31.4kQ1 26 puts: $26.0kQ1 26P/C 0.83Q2 26 calls: $475.5kQ2 26 puts: $11.7kQ2 26P/C 0.02
Numbers
QuarterCallsPutsP/C
Q3 2025$35.0k$102.4k2.93
Q4 2025$1.3k$1850.14
Q1 2026$31.4k$26.0k0.83
Q2 2026$475.5k$11.7k0.02

Biggest buyers

JANE STREET GROUP, LLC Added +483,808+483.8k
MARSHALL WACE, LLP New +395,583+395.6k
Johns Hopkins University New +387,359+387.4k
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP New +290,096+290.1k
Russell Investments Group, Ltd. Added +261,791+261.8k
VANGUARD CAPITAL MANAGEMENT LLC Added +240,483+240.5k
Peapod Lane Capital LLC Added +207,999+208.0k
Round Rock Advisors LLC New +152,841+152.8k
MILLENNIUM MANAGEMENT LLC New +124,186+124.2k
CITADEL ADVISORS LLC Added +120,796+120.8k

Biggest sellers

WEXFORD CAPITAL LP Reduced -9,996,389-10.0m
BlackRock, Inc. Reduced -1,046,863-1.0m
STATE STREET CORP Reduced -320,058-320.1k
GEODE CAPITAL MANAGEMENT, LLC Reduced -304,898-304.9k
GOLDMAN SACHS GROUP INC Reduced -168,561-168.6k
LOS ANGELES CAPITAL MANAGEMENT LLC Sold out -163,259-163.3k
VANGUARD PORTFOLIO MANAGEMENT LLC Sold out -140,145-140.1k
NORTHERN TRUST CORP Reduced -129,948-129.9k
Boston Partners Reduced -85,453-85.5k
ACADIAN ASSET MANAGEMENT LLC Reduced -82,055-82.1k

Biggest calls

CITADEL ADVISORS LLC New $458.6k141.1k shares
GROUP ONE TRADING LLC Added $16.9k5.2k shares

Biggest puts

GROUP ONE TRADING LLC New $11.4k3.5k shares
SIMPLEX TRADING, LLC New $325100 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
WEXFORD CAPITAL LP 13G · exempt (held before listing) filed 2026-06-22 25.1% 12.1m≈ $39.2m 2026-06-22
DAVIDSON CHARLES E 13G · passive investor new · filed 2026-06-22 13.4% new 6.5m≈ $21.0m 2026-06-22

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
202Q4 24: 1 buyingQ4 24: 1 sellingQ1 25: 0 buyingQ1 25: 0 sellingQ1 25Q2 25: 0 buyingQ2 25: 1 sellingQ3 25: 0 buyingQ3 25: 0 sellingQ3 25Q4 25: 1 buyingQ4 25: 0 sellingQ1 26: 0 buyingQ1 26: 0 sellingQ1 26Q2 26: 2 buyingQ2 26: 0 sellingQ3 26: 1 buyingQ3 26: 0 sellingQ3 26
Numbers
QuarterBuyingBoughtSellingSoldSold under a plan
Q4 20241$3.0k1$176.3k—
Q1 20250—0——
Q2 20250—1$213.1k—
Q3 20250—0——
Q4 20251$18.9k0——
Q1 20260—0——
Q2 20262$10.5m0——
Q3 20261$15.0k0——
DateInsiderTradeSharesPrice ValueTheir holding
2026-09-16 Plaumann Mark Lawrence Director Bought 5,000 $3.00 $15.0k5.0k shares new
2026-06-17 DAVIDSON CHARLES E +3 Chief Business Officer, director Bought 4,019,574 $2.60 $10.5m4.0m shares +61%
2026-06-12 Amron Arthur H Director Bought 2,000 $3.28 $6.6k2.0k shares +3%
2026-06-11 Amron Arthur H Director Bought 2,500 $3.22 $8.1k2.5k shares +4%
2026-05-28 Amron Arthur H Director Bought 3,000 $3.25 $9.8k3.0k shares +5%
2026-05-26 Amron Arthur H Director Bought 2,500 $3.24 $8.1k2.5k shares +4%

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 WEXFORD CAPITAL LP 5.38% of their portfolio WEST PALM BEACH, FL 12,071,82312.1m $39.2m $39.2m 5.38% Reduced -10.0m -9,996,389
2 ADAGE CAPITAL PARTNERS GP, L.L.C. 0.02% of their portfolio Boston, MA 4,575,0004.6m $14.9m $14.9m 0.02% Unchanged
3 VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio MALVERN, PA 1,059,6031.1m $3.4m $3.4m 0.00% Added +240.5k +240,483
4 Peapod Lane Capital LLC 1.77% of their portfolio Bedford Hills, NY 807,804807.8k $2.6m $2.6m 1.77% Added +208.0k +207,999
5 DIMENSIONAL FUND ADVISORS LP 0.00% of their portfolio AUSTIN, TX 691,667691.7k $2.2m $2.2m 0.00% Added +5.5k +5,468
6 JANE STREET GROUP, LLC 0.00% of their portfolio NEW YORK, NY 506,662506.7k $1.6m $1.6m 0.00% Added +483.8k +483,808
7 CITADEL ADVISORS LLC 0.00% of their portfolio MIAMI, FL 452,163452.2k $1.5m $1.5m 0.00% Added +120.8k +120,796
8 BlackRock, Inc. 0.00% of their portfolio New York, NY 407,976408.0k $1.3m $1.3m 0.00% Reduced -1.0m -1,046,863
9 MARSHALL WACE, LLP 0.00% of their portfolio LONDON, X0 395,583395.6k $1.3m $1.3m 0.00% New
10 Johns Hopkins University 0.08% of their portfolio BALTIMORE, MD 387,359387.4k $1.3m $1.3m 0.08% New
11 BRIDGEWAY CAPITAL MANAGEMENT, LLC 0.02% of their portfolio HOUSTON, TX 332,313332.3k $1.1m $1.1m 0.02% Unchanged
12 Russell Investments Group, Ltd. 0.00% of their portfolio Seattle, WA 329,821329.8k $1.1m $1.1m 0.00% Added +261.8k +261,791
13 GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio BOSTON, MA 306,028306.0k $995.7k $995.7k 0.00% Reduced -304.9k -304,898
14 RENAISSANCE TECHNOLOGIES LLC 0.00% of their portfolio NEW YORK, NY 292,280292.3k $949.9k $949.9k 0.00% Added +60.3k +60,308
15 ARROWSTREET CAPITAL, LIMITED PARTNERSHIP 0.00% of their portfolio BOSTON, MA 290,096290.1k $942.8k $942.8k 0.00% New
16 Empowered Funds, LLC 0.00% of their portfolio NEWTOWN SQUARE, PA 241,313241.3k $784.3k $784.3k 0.00% Unchanged
17 AQR CAPITAL MANAGEMENT LLC 0.00% of their portfolio Greenwich, CT 177,824177.8k $577.9k $577.9k 0.00% Added +111.1k +111,093
18 VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio MALVERN, PA 161,791161.8k $525.8k $525.8k 0.00% Reduced -8.3k -8,340
19 Round Rock Advisors LLC 0.06% of their portfolio WILTON, CT 152,841152.8k $496.7k $496.7k 0.06% New
20 MORGAN STANLEY 0.00% of their portfolio NEW YORK, NY 133,560133.6k $434.1k $434.1k 0.00% Reduced -19.2k -19,163
21 Centiva Capital, LP 0.01% of their portfolio New York, NY 130,870130.9k $425.3k $425.3k 0.01% Added +19.8k +19,762
22 GSA CAPITAL PARTNERS LLP 0.03% of their portfolio LONDON, X0 129,547129.5k $421.0k $421.0k 0.03% Added +115.6k +115,638
23 MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio NEW YORK, NY 124,186124.2k $403.6k $403.6k 0.00% New
24 ACADIAN ASSET MANAGEMENT LLC 0.00% of their portfolio Boston, MA 122,050122.0k $396.0k $396.0k 0.00% Reduced -82.1k -82,055
25 Marquette Asset Management, LLC 0.05% of their portfolio MINNEAPOLIS, MN 109,826109.8k $356.9k $356.9k 0.05% New
26 STIFEL FINANCIAL CORP 0.00% of their portfolio ST. LOUIS, MO 105,572105.6k $343.1k $343.1k 0.00% Unchanged
27 STATE STREET CORP 0.00% of their portfolio BOSTON, MA 101,864101.9k $331.1k $331.1k 0.00% Reduced -320.1k -320,058
28 BANK OF AMERICA CORP /DE/ 0.00% of their portfolio CHARLOTTE, NC 97,04697.0k $315.4k $315.4k 0.00% Added +71.5k +71,457
29 BNP PARIBAS FINANCIAL MARKETS 0.00% of their portfolio PARIS, I0 92,96493.0k $302.1k $302.1k 0.00% Added +76.2k +76,217
30 FNY Investment Advisers, LLC 0.09% of their portfolio NEW YORK, NY 76,48176.5k $248.0k $248.0k 0.09% New
31 Point72 Asset Management, L.P. 0.00% of their portfolio STAMFORD, CT 72,09172.1k $234.3k $234.3k 0.00% New
32 Boston Partners 0.00% of their portfolio BOSTON, MA 68,93568.9k $224.0k $224.0k 0.00% Reduced -85.5k -85,453
33 Aster Capital Management (DIFC) Ltd 0.05% of their portfolio DUBAI, C0 67,57067.6k $219.6k $219.6k 0.05% New
34 Bank of New York Mellon Corp 0.00% of their portfolio NEW YORK, NY 62,00762.0k $201.5k $201.5k 0.00% Reduced -70.5k -70,532
35 Qube Research & Technologies Ltd 0.00% of their portfolio LONDON, X0 58,85958.9k $191.3k $191.3k 0.00% New
36 TWO SIGMA INVESTMENTS, LP 0.00% of their portfolio NEW YORK, NY 58,53858.5k $190.2k $190.2k 0.00% New
37 NORTHERN TRUST CORP 0.00% of their portfolio CHICAGO, IL 57,18057.2k $185.8k $185.8k 0.00% Reduced -129.9k -129,948
38 GOLDMAN SACHS GROUP INC 0.00% of their portfolio NEW YORK, NY 54,92854.9k $178.5k $178.5k 0.00% Reduced -168.6k -168,561
39 SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.00% of their portfolio BALA CYNWYD, PA 49,92049.9k $162.2k $162.2k 0.00% Added +13.6k +13,621
40 XTX Topco Ltd 0.00% of their portfolio LONDON, X0 49,26149.3k $160.1k $160.1k 0.00% New
41 Walleye Capital LLC 0.00% of their portfolio NEW YORK, NY 49,14149.1k $159.7k $159.7k 0.00% New
42 WELLINGTON MANAGEMENT GROUP LLP 0.00% of their portfolio Boston, MA 47,48647.5k $154.3k $154.3k 0.00% Reduced -20.9k -20,929
43 ALGERT GLOBAL LLC 0.00% of their portfolio SAN FRANCISCO, CA 45,99746.0k $149.5k $149.5k 0.00% New
44 Quadrature Capital Ltd 0.00% of their portfolio LONDON, X0 44,01544.0k $143.0k $143.0k 0.00% New
45 HSBC HOLDINGS PLC 0.00% of their portfolio LONDON, X0 33,70633.7k $108.0k $108.0k 0.00% New
46 HRT FINANCIAL LP 0.00% of their portfolio NEW YORK, NY 30,63230.6k $99.0k $99.0k 0.00% New
47 UBS Group AG 0.00% of their portfolio ZURICH, V8 29,51829.5k $95.9k $95.9k 0.00% Added +21.9k +21,851
48 Connor, Clark & Lunn Investment Management Ltd. 0.00% of their portfolio VANCOUVER, A1 28,58128.6k $92.9k $92.9k 0.00% Added +14.1k +14,071
49 CAPTRUST FINANCIAL ADVISORS 0.00% of their portfolio RALEIGH, NC 26,79926.8k $87.1k $87.1k 0.00% New
50 BARCLAYS PLC 0.00% of their portfolio LONDON, X0 25,55325.6k $83.0k $83.0k 0.00% Added +20.0k +19,972
51 IEQ CAPITAL, LLC 0.00% of their portfolio Foster City, CA 24,39224.4k $79.3k $79.3k 0.00% New
52 Pathstone Holdings, LLC 0.00% of their portfolio ENGLEWOOD, NJ 22,33622.3k $72.6k $72.6k 0.00% New
53 Schonfeld Strategic Advisors LLC 0.00% of their portfolio NEW YORK, NY 16,86416.9k $54.8k $54.8k 0.00% Reduced -1.5k -1,461
54 RHUMBLINE ADVISERS 0.00% of their portfolio BOSTON, MA 16,60916.6k $54.0k $54.0k 0.00% Reduced -16.3k -16,254
55 Archer Investment Corp 0.01% of their portfolio Carmel, IN 16,40016.4k $53.3k $53.3k 0.01% Added +5.2k +5,200
56 AXQ CAPITAL, LP 0.00% of their portfolio JERSEY CITY, NJ 13,90313.9k $45.2k $45.2k 0.00% New
57 Tower Research Capital LLC (TRC) 0.00% of their portfolio NEW YORK, NY 13,47713.5k $43.8k $43.8k 0.00% Added +955 +955
58 Creative Planning 0.00% of their portfolio OVERLAND PARK, KS 13,31713.3k $43.3k $43.3k 0.00% Reduced -3.6k -3,633
59 Mariner, LLC 0.00% of their portfolio Overland Park, KS 13,28713.3k $43.1k $43.1k 0.00% Reduced -13.6k -13,586
60 Virtu Financial LLC 0.00% of their portfolio New York, NY 12,79312.8k $42.0k $42.0k 0.00% New
61 FMR LLC 0.00% of their portfolio BOSTON, MA 12,53112.5k $40.7k $40.7k 0.00% Added +389 +389
62 JPMORGAN CHASE & CO 0.00% of their portfolio NEW YORK, NY 12,38512.4k $36.0k $36.0k 0.00% Added +2.1k +2,110
63 STEINBERGANNA WEALTH MANAGEMENT 0.02% of their portfolio HUNTINGTON, NY 11,56011.6k $37.6k $37.6k 0.02% Reduced -6.8k -6,800
64 PRELUDE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio NEW YORK, NY 10,80010.8k $35.1k $35.1k 0.00% New
65 CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio SAN FRANCISCO, CA 10,73910.7k $34.9k $34.9k 0.00% Reduced -48.1k -48,122
66 Vanguard Global Advisers, LLC 0.00% of their portfolio MALVERN, PA 8,7748.8k $28.5k $28.5k 0.00% Unchanged
67 PNC Financial Services Group, Inc. 0.00% of their portfolio Pittsburgh, PA 7,2177.2k $23.5k $23.5k 0.00% Added +1.5k +1,497
68 ROYAL BANK OF CANADA 0.00% of their portfolio TORONTO, A6 4,5374.5k $14.0k $14.0k 0.00% Added +4.5k +4,536
69 SIMPLEX TRADING, LLC 0.00% of their portfolio CHICAGO, IL 3,4573.5k $11.2k $11.2k 0.00% Reduced -2.1k -2,081
70 UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC 0.00% of their portfolio NEW YORK, NY 1,4161.4k $4.6k $4.6k 0.00% Unchanged
71 Arax Advisory Partners 0.00% of their portfolio NEW YORK, NY 843843 $2.7k $2.7k 0.00% Added +826 +826
72 Allworth Financial LP 0.00% of their portfolio FOLSOM, CA 840840 $2.7k $2.7k 0.00% Added +638 +638
73 Allianz SE 0.00% of their portfolio Munich, 2M 800800 $2.6k $2.6k 0.00% Unchanged
74 GROUP ONE TRADING LLC 0.00% of their portfolio CHICAGO, IL 777777 $2.5k $2.5k 0.00% New
75 Integrated Wealth Concepts LLC 0.00% of their portfolio WALTHAM, MA 524524 $1.7k $1.7k 0.00% New
76 WELLS FARGO & COMPANY/MN 0.00% of their portfolio SAN FRANCISCO, CA 300300 $975 $975 0.00% Reduced -9.2k -9,169
77 EverSource Wealth Advisors, LLC 0.00% of their portfolio BIRMINGHAM, AL 276276 $898 $898 0.00% Added +192 +192
78 ROTHSCHILD INVESTMENT LLC 0.00% of their portfolio CHICAGO, IL 239239 $777 $777 0.00% Added +106 +106
79 Essential Partners LLC 0.00% of their portfolio RANCHO SANTA FE, CA 212212 $689 $689 0.00% Added +192 +192
80 MCGUIRE CAPITAL ADVISORS INC 0.00% of their portfolio BETHANY, OK 200200 $650 $650 0.00% New
81 Westside Investment Management, Inc. 0.00% of their portfolio SANTA MONICA, CA 187187 $608 $608 0.00% Unchanged
82 OSAIC HOLDINGS, INC. 0.00% of their portfolio SCOTTSDALE, AZ 150150 $487 $487 0.00% Reduced -72.3k -72,269
83 Farther Finance Advisors, LLC 0.00% of their portfolio SAN FRANCISCO, CA 107107 $343 $343 0.00% Added +93 +93
84 Basecamp Wealth Advisors LLC 0.00% of their portfolio BELLEVUE, WA 7979 $257 $257 0.00% Added +22 +22
85 True Wealth Design, LLC 0.00% of their portfolio AKRON, OH 3737 $121 $121 0.00% Added +12 +12
86 Transamerica Financial Advisors, LLC 0.00% of their portfolio CEDAR RAPIDS, IA 3131 $100 $100 0.00% Unchanged
87 SJS Investment Consulting Inc. 0.00% of their portfolio SYLVANIA, OH 3030 $98 $98 0.00% Added +13 +13
88 IFP Advisors, Inc 0.00% of their portfolio TAMPA, FL 2727 $88 $88 0.00% Added +22 +22
89 Wealth Enhancement Trust Services, Inc. 0.00% of their portfolio SIOUX FALLS, SD 1717 $55 $55 0.00% New
90 Caitong International Asset Management Co., Ltd 0.00% of their portfolio HONG KONG, K3 1010 $32 $32 0.00% Added +8 +8
91 JPL Wealth Management, LLC 0.00% of their portfolio GREENWOOD VILLAGE, CO 99 $30 $30 0.00% Unchanged
92 Fortitude Family Office, LLC 0.00% of their portfolio SCOTTSDALE, AZ 77 $23 $23 0.00% New
93 CITIGROUP INC 0.00% of their portfolio NEW YORK, NY 11 $3 $3 0.00% Reduced -1.1k -1,126
94 SBI Securities Co., Ltd. 0.00% of their portfolio TOKYO, M0 11 $3 $3 0.00% Reduced -100 -100