Who owns Natural Gas Services Group, Inc. (NGS)
Which tracked institutional funds hold NGS, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See NGS company fundamentals →
Ownership as of the 2026-Q1 13F filings (latest filed 2026-05-18). 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
The tracked-fund tape on NGS is one-sided between 2025-Q4 and 2026-Q1: 56 added or opened and 13 trimmed or exited — on balance accumulating.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
NGS’s largest tracked holder by dollar value, DIMENSIONAL FUND ADVISORS LP, sizes it at 0.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.0pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in NGS divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2025-Q4 and 2026-Q1, across 149 tracked filers holding NGS, 90 increased or opened the position and 52 reduced or closed it; over the same quarter, open-market insider Form 4 buying and selling roughly offset.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in NGS between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 14
- VANGUARD CAPITAL MANAGEMENT LLC$19M
- MARSHALL WACE, LLP$4M
- JANE STREET GROUP, LLC$3M
- VANGUARD PORTFOLIO MANAGEMENT LLC$3M
- VANGUARD FIDUCIARY TRUST CO$3M
- Walleye Capital LLC$2M
Full exits 5
- VANGUARD GROUP INC$22M
- Mill Road Capital Management LLC$4M
- TWO SIGMA ADVISERS, LP$1M
- Perritt Capital Management Inc$572K
- Rothschild Wealth LLC$572K
Largest adds
- TWO SIGMA INVESTMENTS, LP$12M
- MILLENNIUM MANAGEMENT LLC$5M
- Phocas Financial Corp.$5M
- CITADEL ADVISORS LLC$4M
- MORGAN STANLEY$4M
- AMERICAN CENTURY COMPANIES INC$3M
Largest trims
- AWM Investment Company, Inc.$15M
- AMERIPRISE FINANCIAL INC$5M
- CANNELL CAPITAL LLC$4M
- LPL Financial LLC$3M
- Invesco Ltd.$2M
- AEGIS FINANCIAL CORP$429K
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| DIMENSIONAL FUND ADVISORS LP trimmed | 843,797 | $32M | 7.4% | 2026-Q1 |
| BlackRock, Inc. trimmed | 789,780 | $30M | 6.9% | 2026-Q1 |
| AEGIS FINANCIAL CORP trimmed | 587,012 | $22M | 5.2% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 510,995 | $19M | 4.5% | 2026-Q1 |
| WEBER CAPITAL MANAGEMENT LLC /ADV trimmed | 481,764 | $18M | 4.2% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 365,209 | $14M | 3.2% | 2026-Q1 |
| ROYCE & ASSOCIATES LP trimmed | 353,316 | $13M | 3.1% | 2026-Q1 |
| AMERICAN CENTURY COMPANIES INC added | 339,022 | $13M | 3.0% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC trimmed | 337,571 | $13M | 3.0% | 2026-Q1 |
| Pacific Ridge Capital Partners, LLC trimmed | 305,374 | $12M | 2.7% | 2026-Q1 |
| First Eagle Investment Management, LLC trimmed | 287,188 | $11M | 2.5% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 285,813 | $11M | 2.5% | 2026-Q1 |
| MORGAN STANLEY added | 263,206 | $10M | 2.3% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC trimmed | 238,042 | $9M | 2.1% | 2026-Q1 |
| AWM Investment Company, Inc. trimmed | 214,776 | $8M | 1.9% | 2026-Q1 |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | 213,503 | $8M | 1.9% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 212,542 | $8M | 1.9% | 2026-Q1 |
| STATE STREET CORP added | 198,987 | $8M | 1.8% | 2026-Q1 |
| CITADEL ADVISORS LLC added | 192,039 | $7M | 1.7% | 2026-Q1 |
| CANNELL CAPITAL LLC trimmed | 191,681 | $7M | 1.7% | 2026-Q1 |
| Qube Research & Technologies Ltd added | 182,644 | $7M | 1.6% | 2026-Q1 |
| Russell Investments Group, Ltd. added | 179,521 | $7M | 1.6% | 2026-Q1 |
| Phocas Financial Corp. added | 162,465 | $6M | 1.4% | 2026-Q1 |
| RBF Capital, LLC | 140,000 | $5M | 1.2% | 2026-Q1 |
| MARSHALL WACE, LLP added | 114,282 | $4M | 1.0% | 2026-Q1 |
| PRUDENTIAL FINANCIAL INC added | 110,030 | $4M | 1.0% | 2026-Q1 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP added | 97,866 | $4M | 0.9% | 2026-Q1 |
| Empowered Funds, LLC | 96,149 | $4M | 0.8% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 95,881 | $4M | 0.8% | 2026-Q1 |
| Bank of New York Mellon Corp added | 95,419 | $4M | 0.8% | 2026-Q1 |
| RAYMOND JAMES FINANCIAL INC trimmed | 85,866 | $3M | 0.8% | 2026-Q1 |
| NORTHERN TRUST CORP added | 84,632 | $3M | 0.7% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS added | 81,657 | $3M | 0.7% | 2026-Q1 |
| CROWN ADVISORS MANAGEMENT, INC. | 80,000 | $3M | 0.7% | 2026-Q1 |
| JANE STREET GROUP, LLC added | 79,385 | $3M | 0.7% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 78,916 | $3M | 0.7% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 74,951 | $3M | 0.7% | 2026-Q1 |
| Connor, Clark & Lunn Investment Management Ltd. added | 68,418 | $3M | 0.6% | 2026-Q1 |
| Walleye Capital LLC added | 61,270 | $2M | 0.5% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 57,034 | $2M | 0.5% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 54,919 | $2M | 0.5% | 2026-Q1 |
| UBS Group AG added | 54,761 | $2M | 0.5% | 2026-Q1 |
| Invesco Ltd. trimmed | 51,766 | $2M | 0.5% | 2026-Q1 |
| SEI INVESTMENTS CO added | 45,674 | $2M | 0.4% | 2026-Q1 |
| Uniplan Investment Counsel, Inc. new | 43,638 | $2M | 0.4% | 2026-Q1 |
| RICE HALL JAMES & ASSOCIATES, LLC trimmed | 43,568 | $2M | 0.4% | 2026-Q1 |
| Trexquant Investment LP added | 39,865 | $2M | 0.4% | 2026-Q1 |
| D. E. Shaw & Co., Inc. added | 39,619 | $1M | 0.3% | 2026-Q1 |
| WHITE PINE CAPITAL LLC trimmed | 38,363 | $1M | 0.3% | 2026-Q1 |
| Point72 Asset Management, L.P. new | 37,271 | $1M | 0.3% | 2026-Q1 |
| Informed Momentum Co LLC added | 35,256 | $1M | 0.3% | 2026-Q1 |
| FIRST TRUST ADVISORS LP added | 35,035 | $1M | 0.3% | 2026-Q1 |
| SIMPLEX TRADING, LLC added | 33,348 | $1M | 0.3% | 2026-Q1 |
| NEW YORK STATE COMMON RETIREMENT FUND added | 31,605 | $1M | 0.3% | 2026-Q1 |
| TrueWealth Advisors, LLC trimmed | 30,550 | $1M | 0.3% | 2026-Q1 |
| Steward Partners Investment Advisory, LLC added | 29,943 | $1M | 0.3% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 28,971 | $1M | 0.3% | 2026-Q1 |
| Illumine Investment Management, LLC new | 27,985 | $1M | 0.2% | 2026-Q1 |
| Calamos Advisors LLC added | 26,046 | $983K | 0.2% | 2026-Q1 |
| Quadrature Capital Ltd added | 23,869 | $901K | 0.2% | 2026-Q1 |
| Assenagon Asset Management S.A. trimmed | 21,662 | $818K | 0.2% | 2026-Q1 |
| STIFEL FINANCIAL CORP trimmed | 20,089 | $758K | 0.2% | 2026-Q1 |
| Jump Financial, LLC added | 18,981 | $716K | 0.2% | 2026-Q1 |
| State of Wyoming added | 18,540 | $700K | 0.2% | 2026-Q1 |
| Creative Planning added | 18,011 | $680K | 0.2% | 2026-Q1 |
| North Star Investment Management Corp. new | 17,000 | $642K | 0.1% | 2026-Q1 |
| ACADIAN ASSET MANAGEMENT LLC trimmed | 16,659 | $628K | 0.1% | 2026-Q1 |
| FMR LLC added | 15,940 | $602K | 0.1% | 2026-Q1 |
| STRS OHIO added | 15,800 | $596K | 0.1% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 15,631 | $590K | 0.1% | 2026-Q1 |
| GSA CAPITAL PARTNERS LLP trimmed | 15,243 | $575K | 0.1% | 2026-Q1 |
| Nuveen, LLC | 15,054 | $568K | 0.1% | 2026-Q1 |
| BRASADA CAPITAL MANAGEMENT, LP | 15,000 | $567K | 0.1% | 2026-Q1 |
| ARTHUR M. COHEN & ASSOCIATES, LLC | 14,390 | $538K | 0.1% | 2026-Q1 |
| LAZARD ASSET MANAGEMENT LLC added | 14,177 | $535K | 0.1% | 2026-Q1 |
| Kestra Advisory Services, LLC added | 13,000 | $491K | 0.1% | 2026-Q1 |
| HRT FINANCIAL LP trimmed | 12,880 | $486K | 0.1% | 2026-Q1 |
| RHUMBLINE ADVISERS added | 12,779 | $482K | 0.1% | 2026-Q1 |
| PRINCIPAL FINANCIAL GROUP INC new | 12,725 | $480K | 0.1% | 2026-Q1 |
| Voleon Capital Management LP new | 11,338 | $428K | 0.1% | 2026-Q1 |
| STATE OF WISCONSIN INVESTMENT BOARD added | 11,312 | $427K | 0.1% | 2026-Q1 |
| Boston Partners trimmed | 11,014 | $416K | 0.1% | 2026-Q1 |
| R Squared Ltd added | 10,594 | $400K | 0.1% | 2026-Q1 |
| Numerai GP LLC new | 10,554 | $398K | 0.1% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 10,335 | $390K | 0.1% | 2026-Q1 |
| Brevan Howard Capital Management LP new | 10,253 | $387K | 0.1% | 2026-Q1 |
| Squarepoint Ops LLC trimmed | 10,146 | $383K | 0.1% | 2026-Q1 |
| PDT Partners, LLC trimmed | 10,075 | $380K | 0.1% | 2026-Q1 |
| FRANKLIN RESOURCES INC trimmed | 10,058 | $380K | 0.1% | 2026-Q1 |
| VANGUARD GROUP INC added | 640,540 | $22M | 5.0% | 2025-Q4 stale |
| Acuitas Investments, LLC added | 216,700 | $6M | 1.4% | 2025-Q3 stale |
| Mill Road Capital Management LLC trimmed | 109,000 | $4M | 0.9% | 2025-Q4 stale |
| Inspire Investing, LLC added | 39,094 | $1M | 0.3% | 2025-Q3 stale |
| TWO SIGMA ADVISERS, LP added | 32,030 | $1M | 0.3% | 2025-Q4 stale |
| JACOBS LEVY EQUITY MANAGEMENT, INC | 22,915 | $641K | 0.1% | 2025-Q3 stale |
| Rothschild Wealth LLC new | 17,000 | $572K | 0.1% | 2025-Q4 stale |
| Perritt Capital Management Inc added | 17,000 | $572K | 0.1% | 2025-Q4 stale |
| ExodusPoint Capital Management, LP added | 14,105 | $395K | 0.1% | 2025-Q3 stale |
| HighTower Advisors, LLC added | 14,723 | $380K | 0.1% | 2025-Q2 stale |
| WELLINGTON MANAGEMENT GROUP LLP trimmed | 14,347 | $370K | 0.1% | 2025-Q2 stale |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.