MNTK · Montauk Renewables, Inc. · Shareholders & Ownership

$2.13 +0.07 (+3.40%)

Russell 2000 member Rebalance outlook locked

Market Cap

$293.22M

142.34M

Volume · Oct 23 392K Avg daily vol (3M) 489.03K

Every disclosed holder of MNTK in one list: 13F institutions, Schedule 13D and 13G filers, insiders (Forms 3, 4 and 5) and registered funds, each from its own latest filing. Holders nest by CIK and SEC reporting links, never by name, and each is summed once.

How the holder list picks a filing →

Who Owns MNTK

13F quarter Sep 30, 2026, combined view: filers that have not filed yet carry their Jun 30, 2026 positions

Holder group	Holders	Shares	% Out	Summed
Institutional (13F)	89	21,336,662	14.99%	Yes
Insiders (Forms 3, 4, 5)	7	24,941,393	17.52%	Yes
13D/G-only blocks	1	35,878	0.03%	Yes
Remaining	—	96,027,206	67.46%	Rest
Registered funds (N-PORT, not summed)	103	10,443,931	7.34%	No

Shares outstanding: 142,341,139, the issuer's latest cover-page count restated onto today's split basis.

13D/G-only counts each filer's latest 13D or 13G that no 13F report of the listing contains, that names no 13F filer and that no counted insider files. Funds are never summed: their shares sit inside their advisers' 13F reports.

Holders of MNTK

One row per holder Every filing By ultimate parent

All 13F Funds Insiders 13D/G Non-US

#	Holder	Shares	% Out	Change	As of	Notes
1	Aktiv Investment Management (Pty) Ltd 13D CIK 2092344 · Unknown · Nov 3, 2025 not summed	22,297,688	15.67%	—	Nov 3, 2025	not summed
1.1	Aktiv Investment Management (Pty) Ltd Insider CIK 2092344 · Nov 3, 2025 10% Owner, issuer-wide	22,297,788	15.67%	—	Nov 3, 2025	10% Owner, issuer-wide
2	BlackRock, Inc. 13F CIK 2012383 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	4,709,893	3.31%	+490,896	Jun 30, 2026	carried, not yet filed for the newest quarter
2.1	iShares Russell 2000 ETF Fund S000004344 · Registered fund · Jun 30, 2026 iShares Trust, not summed	1,689,345	1.19%	+116,005	Jun 30, 2026	iShares Trust, not summed
2.2	iShares Russell 2000 Value ETF Fund S000004342 · Registered fund · Jun 30, 2026 iShares Trust, not summed	485,528	0.34%	+40,527	Jun 30, 2026	iShares Trust, not summed
2.3	iShares Micro-Cap ETF Fund S000004439 · Registered fund · Jun 30, 2026 iShares Trust, not summed	226,441	0.16%	—	Jun 30, 2026	iShares Trust, not summed
2.4	iShares Russell 2000 Growth ETF Fund S000004343 · Registered fund · Jun 30, 2026 iShares Trust, not summed	207,959	0.15%	+102,601	Jun 30, 2026	iShares Trust, not summed
2.5	Master Small Cap Index Series Fund S000002716 · Registered fund · Jun 30, 2026 Quantitative Master Series LLC, not summed	108,509	0.08%	0	Jun 30, 2026	Quantitative Master Series LLC, not summed
3	VANGUARD CAPITAL MANAGEMENT LLC 13F CIK 2100119 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	2,706,900	1.90%	+18,186	Jun 30, 2026	carried, not yet filed for the newest quarter
4	VANGUARD TOTAL STOCK MARKET INDEX FUND Fund S000002848 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	1,900,119	1.33%	0	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
5	GEODE CAPITAL MANAGEMENT, LLC 13F CIK 1214717 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	1,879,292	1.32%	+120,014	Jun 30, 2026	carried, not yet filed for the newest quarter
6	Baader Bank Aktiengesellschaft 13F CIK 1542629 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	1,605,000	1.13%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
7	STATE STREET CORP 13F CIK 93751 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	1,369,693	0.96%	+4,220	Jun 30, 2026	carried, not yet filed for the newest quarter
7.1	STATE STREET SMALL/MID CAP EQUITY INDEX PORTFOLIO Fund S000050332 · Registered fund · Jun 30, 2026 STATE STREET INSTITUTIONAL INVESTMENT TRUST, not summed	28,500	0.02%	+9,600	Jun 30, 2026	STATE STREET INSTITUTIONAL INVESTMENT TRUST, not summed
7.2	State Street Total Return V.I.S. Fund Fund S000001637 · Registered fund · Jun 30, 2026 STATE STREET VARIABLE INSURANCE SERIES FUNDS INC, not summed	1,071	0.00%	-1,385	Jun 30, 2026	STATE STREET VARIABLE INSURANCE SERIES FUNDS INC, not summed
8	McClain Sean F Insider CIK 1833634 · May 20, 2026 Director, President and CEO, issuer-wide	1,141,172	0.80%	+383,183	May 20, 2026	Director, President and CEO, issuer-wide
9	BARCLAYS PLC 13F CIK 312069 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	953,510	0.67%	-85,407	Jun 30, 2026	carried, not yet filed for the newest quarter
10	AMERICAN CENTURY COMPANIES INC 13F CIK 748054 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	950,442	0.67%	-4,026	Jun 30, 2026	carried, not yet filed for the newest quarter
11	Avantis U.S. Small Cap Value ETF Fund S000066459 · Registered fund · May 31, 2026 American Century ETF Trust, not summed	774,101	0.54%	-626	May 31, 2026	American Century ETF Trust, not summed
12	VANGUARD EXTENDED MARKET INDEX FUND Fund S000002841 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	745,159	0.52%	+33,246	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
13	CHARLES SCHWAB INVESTMENT MANAGEMENT INC 13F CIK 884546 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	539,334	0.38%	+18,723	Jun 30, 2026	carried, not yet filed for the newest quarter
13.1	Schwab U.S. Small-Cap ETF Fund S000026636 · Registered fund · May 31, 2026 SCHWAB STRATEGIC TRUST, not summed	316,178	0.22%	-5,014	May 31, 2026	SCHWAB STRATEGIC TRUST, not summed
13.2	Schwab Small-Cap Index Fund Fund S000005912 · Registered fund · Jul 31, 2026 SCHWAB CAPITAL TRUST, not summed	170,693	0.12%	+24,383	Jul 31, 2026	SCHWAB CAPITAL TRUST, not summed
13.3	Schwab U.S. Broad Market ETF Fund S000026631 · Registered fund · May 31, 2026 SCHWAB STRATEGIC TRUST, not summed	52,526	0.04%	+479	May 31, 2026	SCHWAB STRATEGIC TRUST, not summed
14	NORTHERN TRUST CORP 13F CIK 73124 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	536,057	0.38%	+30,683	Jun 30, 2026	carried, not yet filed for the newest quarter
14.1	Small Cap Index Fund Fund S000001245 · Registered fund · Jun 30, 2026 Northern Funds, not summed	36,783	0.03%	-4,040	Jun 30, 2026	Northern Funds, not summed
15	Van Asdalan Kevin A Insider CIK 1833543 · May 20, 2026 CFO and Treasurer, issuer-wide	497,493	0.35%	+302,982	May 20, 2026	CFO and Treasurer, issuer-wide
16	Shaw James A Insider CIK 1833544 · May 20, 2026 Vice President of Operations, issuer-wide	477,387	0.34%	+282,842	May 20, 2026	Vice President of Operations, issuer-wide
17	Ciroli John Insider CIK 1833517 · May 20, 2026 See Remarks, issuer-wide	470,772	0.33%	+302,982	May 20, 2026	See Remarks, issuer-wide
18	VANGUARD PORTFOLIO MANAGEMENT LLC 13F CIK 2100121 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	469,053	0.33%	+80,134	Jun 30, 2026	carried, not yet filed for the newest quarter
19	DIMENSIONAL FUND ADVISORS LP 13F CIK 354204 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	448,818	0.32%	-287,766	Jun 30, 2026	carried, not yet filed for the newest quarter
19.1	Dimensional U.S. Core Equity 2 ETF Fund S000070903 · Registered fund · Jul 31, 2026 Dimensional ETF Trust, not summed	45,690	0.03%	0	Jul 31, 2026	Dimensional ETF Trust, not summed
19.2	U.S. SMALL CAP PORTFOLIO Fund S000000971 · Registered fund · Jul 31, 2026 DFA INVESTMENT DIMENSIONS GROUP INC, not summed	16,807	0.01%	-114,242	Jul 31, 2026	DFA INVESTMENT DIMENSIONS GROUP INC, not summed
19.3	Dimensional VA U.S. Targeted Value Portfolio Fund S000000953 · Registered fund · Jul 31, 2026 DFA INVESTMENT DIMENSIONS GROUP INC, not summed	16,153	0.01%	0	Jul 31, 2026	DFA INVESTMENT DIMENSIONS GROUP INC, not summed
20	VANGUARD FIDUCIARY TRUST CO 13F CIK 933478 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	438,777	0.31%	+6,509	Jun 30, 2026	carried, not yet filed for the newest quarter
21	FIRST TRUST ADVISORS LP 13F CIK 1125816 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	381,889	0.27%	+69,939	Jun 30, 2026	carried, not yet filed for the newest quarter
21.1	First Trust NASDAQ Clean Edge Green Energy Index Fund Fund S000015169 · Registered fund · Jun 30, 2026 First Trust Exchange-Traded Fund, not summed	352,551	0.25%	+51,977	Jun 30, 2026	First Trust Exchange-Traded Fund, not summed
22	GOLDMAN SACHS GROUP INC 13F CIK 886982 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	377,277	0.27%	+46,088	Jun 30, 2026	carried, not yet filed for the newest quarter
22.1	Goldman Sachs ActiveBeta(R) U.S. Small Cap Equity ETF Fund S000048296 · Registered fund · May 31, 2026 Goldman Sachs ETF Trust, not summed	54,617	0.04%	+727	May 31, 2026	Goldman Sachs ETF Trust, not summed
22.2	Goldman Sachs Absolute Return Tracker Fund Fund S000020314 · Registered fund · Jun 30, 2026 GOLDMAN SACHS TRUST, not summed	27,644	0.02%	+16,093	Jun 30, 2026	GOLDMAN SACHS TRUST, not summed
23	Hosking Partners LLP 13F CIK 1650135 · Registered investment adviser · Sep 30, 2026	370,553	0.26%	-19,964	Sep 30, 2026
24	RENAISSANCE TECHNOLOGIES LLC 13F CIK 1037389 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	364,800	0.26%	+10,200	Jun 30, 2026	carried, not yet filed for the newest quarter
25	VANGUARD RUSSELL 2000 INDEX FUND Fund S000030003 · Registered fund · May 31, 2026 VANGUARD SCOTTSDALE FUNDS, not summed	348,926	0.25%	+16,360	May 31, 2026	VANGUARD SCOTTSDALE FUNDS, not summed
26	JPMORGAN CHASE & CO 13F CIK 19617 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	270,982	0.19%	+108,730	Jun 30, 2026	carried, not yet filed for the newest quarter
27	AQR CAPITAL MANAGEMENT LLC 13F CIK 1167557 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	238,152	0.17%	+199,801	Jun 30, 2026	carried, not yet filed for the newest quarter
28	GSA CAPITAL PARTNERS LLP 13F CIK 1362033 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	201,055	0.14%	-88,839	Jun 30, 2026	carried, not yet filed for the newest quarter
29	JTC Employer Solutions Trustee Ltd 13F CIK 1875645 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	197,859	0.14%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
30	Bank of New York Mellon Corp 13F CIK 1390777 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	195,907	0.14%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
31	MORGAN STANLEY 13F CIK 895421 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	167,182	0.12%	-94,216	Jun 30, 2026	carried, not yet filed for the newest quarter
32	Nuveen, LLC 13F CIK 1871926 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	162,044	0.11%	+22,436	Jun 30, 2026	carried, not yet filed for the newest quarter
32.1	Nuveen Small Cap Blend Index Fund Fund S000005367 · Registered fund · Jul 31, 2026 TIAA-CREF Funds, not summed	106,302	0.07%	+22,436	Jul 31, 2026	TIAA-CREF Funds, not summed
32.2	Nuveen Equity Index Fund Fund S000005360 · Registered fund · Jul 31, 2026 TIAA-CREF Funds, not summed	50,710	0.04%	0	Jul 31, 2026	TIAA-CREF Funds, not summed
32.3	TIAA Separate Account VA-1 - Stock Index Account Fund S000005098 · Registered fund · Jun 30, 2026 TIAA Separate Account VA-1, not summed	1,899	0.00%	0	Jun 30, 2026	TIAA Separate Account VA-1, not summed
32.4	Nuveen Life Stock Index Fund Fund S000005094 · Registered fund · Jun 30, 2026 TIAA-CREF Life Funds, not summed	1,443	0.00%	0	Jun 30, 2026	TIAA-CREF Life Funds, not summed
33	ALLIANCEBERNSTEIN L.P. 13F CIK 1109448 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	142,138	0.10%	+44,618	Jun 30, 2026	carried, not yet filed for the newest quarter
34	Caprock Group, LLC 13F CIK 1610769 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	119,801	0.08%	+119,801	Jun 30, 2026	carried, not yet filed for the newest quarter
35	J. Derek Lewis & Associates Inc. 13F CIK 2077884 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	106,500	0.07%	+21,500	Jun 30, 2026	carried, not yet filed for the newest quarter
36	D. E. Shaw & Co., Inc. 13F CIK 1009207 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	101,497	0.07%	-16,759	Jun 30, 2026	carried, not yet filed for the newest quarter
37	Avantis U.S. Small Cap Equity ETF Fund S000074835 · Registered fund · May 31, 2026 American Century ETF Trust, not summed	96,272	0.07%	-3,400	May 31, 2026	American Century ETF Trust, not summed
38	RHUMBLINE ADVISERS 13F CIK 1115418 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	94,756	0.07%	+1,678	Jun 30, 2026	carried, not yet filed for the newest quarter
39	Rathbones Group PLC 13F CIK 1351991 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	92,000	0.06%	-10,000	Jun 30, 2026	carried, not yet filed for the newest quarter
40	STOREBRAND ASSET MANAGEMENT AS 13F CIK 1685676 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	88,075	0.06%	+5,900	Jun 30, 2026	carried, not yet filed for the newest quarter
41	ACADIAN ASSET MANAGEMENT LLC 13F CIK 916542 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	81,760	0.06%	+25,654	Jun 30, 2026	carried, not yet filed for the newest quarter
42	MARSHALL WACE, LLP 13F CIK 1318757 · Exempt reporting adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	80,526	0.06%	-124,110	Jun 30, 2026	carried, not yet filed for the newest quarter
43	EQ/2000 Managed Volatility Portfolio Fund S000025800 · Registered fund · Jun 30, 2026 EQ Advisors Trust, not summed	80,237	0.06%	0	Jun 30, 2026	EQ Advisors Trust, not summed
44	UBS Group AG 13F CIK 1610520 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	68,630	0.05%	+26,763	Jun 30, 2026	carried, not yet filed for the newest quarter
45	CITADEL ADVISORS LLC 13F CIK 1423053 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	58,826	0.04%	+58,826	Jun 30, 2026	carried, not yet filed for the newest quarter
46	WELLS FARGO & COMPANY/MN 13F CIK 72971 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	58,510	0.04%	+33,296	Jun 30, 2026	carried, not yet filed for the newest quarter
47	Russell Investments Group, Ltd. 13F CIK 1692234 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	56,498	0.04%	+25,205	Jun 30, 2026	carried, not yet filed for the newest quarter
47.1	U.S. Small Cap Equity Fund Fund S000001586 · Registered fund · Jul 31, 2026 RUSSELL INVESTMENT CO, not summed	139,585	0.10%	—	Jul 31, 2026	RUSSELL INVESTMENT CO, not summed
48	STRS OHIO 13F CIK 820478 · Pension or benefit plan · Jun 30, 2026 carried, not yet filed for the newest quarter	48,800	0.03%	+8,800	Jun 30, 2026	carried, not yet filed for the newest quarter
49	DEUTSCHE BANK AG\ 13F CIK 948046 · Non-US institution · Jun 30, 2026 carried, not yet filed for the newest quarter	48,632	0.03%	+1,625	Jun 30, 2026	carried, not yet filed for the newest quarter
49.1	DWS Small Cap Index VIP Fund S000006223 · Registered fund · Jun 30, 2026 DEUTSCHE DWS INVESTMENTS VIT FUNDS, not summed	10,307	0.01%	0	Jun 30, 2026	DEUTSCHE DWS INVESTMENTS VIT FUNDS, not summed
50	LVIP State Street Small-Cap Index Fund Fund S000015974 · Registered fund · Jun 30, 2026 LINCOLN VARIABLE INSURANCE PRODUCTS TRUST, not summed	47,600	0.03%	0	Jun 30, 2026	LINCOLN VARIABLE INSURANCE PRODUCTS TRUST, not summed

4 more nested rows are not shown here; Every filing lists them all.

Shares are restated onto today's split basis. Change compares each row with the same holder's previous filing in the same source; a dash means there is none to compare. Nested 13D/G, insider and fund rows are not summed, since a 13F report already holds them.

Showing 1–50 of 162 holders

Create a free account to page through every holder, filter by source and group by ultimate parent.

Key facts CIK 1826600 CUSIP 61218C103 13F (30d) 11 filings 11 filers Visit website Investor relations