Who owns Neuronetics, Inc. (STIM)
Which tracked institutional funds hold STIM, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See STIM 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
7 tracked funds added or opened STIM while 4 trimmed or exited it between 2025-Q4 and 2026-Q1 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.
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
STIM’s largest tracked holder by dollar value, Madryn Asset Management, LP, sizes it at 78.5% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 78.5pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in STIM 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 99 tracked filers holding STIM, 53 increased or opened the position and 47 reduced or closed it; over the same quarter, open-market insider Form 4s were net purchases.
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 STIM 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 1
- VANGUARD CAPITAL MANAGEMENT LLC$3M
Full exits 2
- VANGUARD GROUP INC$4M
- RENAISSANCE TECHNOLOGIES LLC$655K
Largest adds
- Madryn Asset Management, LP$1M
- FourWorld Capital Management LLC$874K
- UBS Group AG$565K
- AdvisorShares Investments LLC$521K
- BALYASNY ASSET MANAGEMENT L.P.$456K
- STATE STREET CORP$416K
Largest trims
- JANE STREET GROUP, LLC$1M
- SUSQUEHANNA INTERNATIONAL GROUP, LLP$318K
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 |
|---|---|---|---|---|
| Madryn Asset Management, LP | 18,475,893 | $27M | 34.0% | 2026-Q1 |
| UBS Group AG added | 2,870,598 | $4M | 5.3% | 2026-Q1 |
| BALYASNY ASSET MANAGEMENT L.P. added | 2,743,768 | $4M | 5.0% | 2026-Q1 |
| BlackRock, Inc. trimmed | 2,318,537 | $3M | 4.3% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 2,047,975 | $3M | 3.8% | 2026-Q1 |
| Lane Generational LLC added | 1,774,624 | $3M | 3.3% | 2026-Q1 |
| FourWorld Capital Management LLC added | 1,489,322 | $2M | 2.7% | 2026-Q1 |
| MASTERS CAPITAL MANAGEMENT LLC | 1,000,000 | $1M | 1.8% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 958,989 | $1M | 1.8% | 2026-Q1 |
| STATE STREET CORP added | 842,547 | $1M | 1.6% | 2026-Q1 |
| Ikarian Capital, LLC | 701,182 | $1M | 1.3% | 2026-Q1 |
| WEXFORD CAPITAL LP added | 700,961 | $1M | 1.3% | 2026-Q1 |
| AdvisorShares Investments LLC added | 617,193 | $895K | 1.1% | 2026-Q1 |
| HighTower Advisors, LLC trimmed | 562,370 | $815K | 1.0% | 2026-Q1 |
| NORTHERN TRUST CORP trimmed | 277,378 | $402K | 0.5% | 2026-Q1 |
| Dauntless Investment Group, LLC added | 269,208 | $390K | 0.5% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 258,034 | $374K | 0.5% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC trimmed | 233,590 | $339K | 0.4% | 2026-Q1 |
| JBF Capital, Inc. | 233,166 | $338K | 0.4% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 221,170 | $321K | 0.4% | 2026-Q1 |
| Massar Capital Management, LP | 221,000 | $320K | 0.4% | 2026-Q1 |
| BOOTHBAY FUND MANAGEMENT, LLC added | 189,263 | $274K | 0.3% | 2026-Q1 |
| Centiva Capital, LP added | 169,319 | $246K | 0.3% | 2026-Q1 |
| XTX Topco Ltd trimmed | 146,155 | $212K | 0.3% | 2026-Q1 |
| Nuveen, LLC added | 123,089 | $178K | 0.2% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 116,680 | $169K | 0.2% | 2026-Q1 |
| CITIZENS FINANCIAL GROUP INC/RI added | 110,953 | $161K | 0.2% | 2026-Q1 |
| ADAR1 Capital Management, LLC new | 100,000 | $145K | 0.2% | 2026-Q1 |
| HRT FINANCIAL LP added | 100,620 | $145K | 0.2% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 98,095 | $142K | 0.2% | 2026-Q1 |
| ROYAL BANK OF CANADA added | 95,848 | $140K | 0.2% | 2026-Q1 |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | 95,205 | $138K | 0.2% | 2026-Q1 |
| VestGen Advisors, LLC new | 100,413 | $128K | 0.2% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 86,481 | $125K | 0.2% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 82,123 | $119K | 0.2% | 2026-Q1 |
| GAMCO INVESTORS, INC. ET AL | 79,200 | $115K | 0.1% | 2026-Q1 |
| Bank of New York Mellon Corp | 78,605 | $114K | 0.1% | 2026-Q1 |
| CITADEL ADVISORS LLC added | 76,597 | $111K | 0.1% | 2026-Q1 |
| SEI INVESTMENTS CO added | 76,046 | $110K | 0.1% | 2026-Q1 |
| Invesco Ltd. added | 72,382 | $105K | 0.1% | 2026-Q1 |
| CITIGROUP INC added | 56,628 | $82K | 0.1% | 2026-Q1 |
| Cruiser Capital Advisors, LLC | 48,900 | $71K | 0.1% | 2026-Q1 |
| DEUTSCHE BANK AG\ | 45,793 | $66K | 0.1% | 2026-Q1 |
| RHUMBLINE ADVISERS trimmed | 41,843 | $61K | 0.1% | 2026-Q1 |
| MORGAN STANLEY trimmed | 40,073 | $58K | 0.1% | 2026-Q1 |
| Arax Advisory Partners new | 39,123 | $57K | 0.1% | 2026-Q1 |
| GABELLI FUNDS LLC | 38,000 | $55K | 0.1% | 2026-Q1 |
| Squarepoint Ops LLC added | 37,616 | $55K | 0.1% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ | 36,861 | $54K | 0.1% | 2026-Q1 |
| Pathstone Holdings, LLC | 32,231 | $47K | 0.1% | 2026-Q1 |
| Schonfeld Strategic Advisors LLC added | 31,751 | $46K | 0.1% | 2026-Q1 |
| VANGUARD GROUP INC trimmed | 2,582,382 | $4M | 4.5% | 2025-Q4 stale |
| Manatuck Hill Partners, LLC | 920,000 | $3M | 4.1% | 2025-Q2 stale |
| Ghisallo Capital Management LLC new | 400,000 | $1M | 1.9% | 2025-Q1 stale |
| Cubist Systematic Strategies, LLC added | 286,571 | $1M | 1.3% | 2025-Q1 stale |
| Walleye Capital LLC added | 242,354 | $892K | 1.1% | 2025-Q1 stale |
| AWM Investment Company, Inc. | 245,924 | $858K | 1.1% | 2025-Q2 stale |
| JOSH ARNOLD INVESTMENT CONSULTANT, LLC new | 200,000 | $736K | 0.9% | 2025-Q1 stale |
| RENAISSANCE TECHNOLOGIES LLC added | 474,900 | $655K | 0.8% | 2025-Q4 stale |
| EHP Funds Inc. new | 209,385 | $572K | 0.7% | 2025-Q3 stale |
| MARSHALL WACE, LLP trimmed | 286,045 | $395K | 0.5% | 2025-Q4 stale |
| Informed Momentum Co LLC trimmed | 104,597 | $385K | 0.5% | 2025-Q1 stale |
| CenterBook Partners LP trimmed | 106,650 | $372K | 0.5% | 2025-Q2 stale |
| GSA CAPITAL PARTNERS LLP trimmed | 97,889 | $360K | 0.5% | 2025-Q1 stale |
| Sanctuary Advisors, LLC | 88,931 | $327K | 0.4% | 2025-Q3 stale |
| Bay Colony Advisory Group, Inc d/b/a Bay Colony Advisors added | 86,919 | $303K | 0.4% | 2025-Q2 stale |
| TWO SIGMA INVESTMENTS, LP trimmed | 198,745 | $274K | 0.3% | 2025-Q4 stale |
| NKCFO LLC trimmed | 75,000 | $262K | 0.3% | 2025-Q2 stale |
| KESTRA PRIVATE WEALTH SERVICES, LLC new | 68,977 | $254K | 0.3% | 2025-Q1 stale |
| TWO SIGMA ADVISERS, LP added | 169,000 | $233K | 0.3% | 2025-Q4 stale |
| Aristides Capital LLC added | 136,400 | $188K | 0.2% | 2025-Q4 stale |
| Diametric Capital, LP new | 51,145 | $188K | 0.2% | 2025-Q1 stale |
| McAdam, LLC new | 50,791 | $187K | 0.2% | 2025-Q1 stale |
| GatePass Capital, LLC | 47,172 | $165K | 0.2% | 2025-Q2 stale |
| Marex Group plc added | 60,200 | $164K | 0.2% | 2025-Q3 stale |
| Qube Research & Technologies Ltd added | 108,208 | $149K | 0.2% | 2025-Q4 stale |
| HBK Sorce Advisory LLC new | 38,680 | $142K | 0.2% | 2025-Q1 stale |
| Caption Management, LLC added | 92,501 | $128K | 0.2% | 2025-Q4 stale |
| Jain Global LLC new | 30,783 | $113K | 0.1% | 2025-Q1 stale |
| MYDA Advisors LLC added | 30,000 | $110K | 0.1% | 2025-Q1 stale |
| Virtu Financial LLC new | 26,133 | $96K | 0.1% | 2025-Q1 stale |
| LPL Financial LLC added | 35,100 | $96K | 0.1% | 2025-Q3 stale |
| Gordian Capital Singapore Pte Ltd new | 24,000 | $90K | 0.1% | 2025-Q1 stale |
| D. E. Shaw & Co., Inc. trimmed | 31,628 | $86K | 0.1% | 2025-Q3 stale |
| Jump Financial, LLC trimmed | 28,000 | $76K | 0.1% | 2025-Q3 stale |
| OMERS ADMINISTRATION Corp trimmed | 27,000 | $74K | 0.1% | 2025-Q3 stale |
| PRELUDE CAPITAL MANAGEMENT, LLC trimmed | 20,010 | $74K | 0.1% | 2025-Q1 stale |
| Atom Investors LP new | 26,854 | $73K | 0.1% | 2025-Q3 stale |
| RAYMOND JAMES FINANCIAL INC added | 24,164 | $66K | 0.1% | 2025-Q3 stale |
| Caitong International Asset Management Co., Ltd added | 46,003 | $63K | 0.1% | 2025-Q4 stale |
| PRUDENTIAL FINANCIAL INC trimmed | 15,200 | $56K | 0.1% | 2025-Q1 stale |
| BlueCrest Capital Management Ltd added | 40,000 | $55K | 0.1% | 2025-Q4 stale |
| Point72 Asia (Singapore) Pte. Ltd. new | 14,980 | $55K | 0.1% | 2025-Q1 stale |
| Tradewinds, LLC. trimmed | 36,437 | $50K | 0.1% | 2025-Q4 stale |
| Larson Financial Group LLC added | 17,813 | $49K | 0.1% | 2025-Q3 stale |
| Assenagon Asset Management S.A. trimmed | 13,761 | $48K | 0.1% | 2025-Q2 stale |
| NATIONAL BANK OF CANADA /FI/ added | 32,000 | $44K | 0.1% | 2025-Q4 stale |
| Capula Management Ltd new | 11,829 | $44K | 0.1% | 2025-Q1 stale |
| WOLVERINE TRADING, LLC added | 16,332 | $43K | 0.1% | 2025-Q3 stale |
| FORA Capital, LLC new | 11,483 | $42K | 0.1% | 2025-Q1 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.