TransMedics Group, Inc. (TMDX) Ownership
TMDX ownership summary
as of October 18, 2026- Institutions
- 103.0% of shares outstanding
- Insiders
- 3.64% of shares outstanding
- Shares outstanding
- 34.7M
- Float
- 33.6M shares available to trade
- Short interest
- 38.40% 8.6M shares short
- Days to cover
- 11.71 short interest up 7.2% vs prior month
- Institutions 102.98%
- Insiders 3.64%
TMDX top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | BlackRock Inc | 16.14% | 5.6M | $396.1M | +303,218 (+5.7%) | June 30, 2026 |
| 2 | FMR Inc | 14.80% | 5.1M | $363.3M | +37,085 (+0.7%) | June 30, 2026 |
| 3 | Vanguard Portfolio Management, LLC | 5.58% | 1.9M | $136.9M | +14,454 (+0.8%) | June 30, 2026 |
| 4 | Vanguard Capital Management, LLC | 4.32% | 1.5M | $106.0M | +19,448 (+1.3%) | June 30, 2026 |
| 5 | State Street Corp | 4.10% | 1.4M | $100.5M | +100,942 (+7.7%) | June 30, 2026 |
| 6 | Delaware Management Holdings Inc | 2.63% | 910K | $64.4M | +24,654 (+2.8%) | June 30, 2026 |
| 7 | Geode Capital Management, LLC | 2.58% | 895K | $63.3M | +55,758 (+6.6%) | June 30, 2026 |
| 8 | Hood River Capital Management LLC | 2.17% | 751K | $53.2M | +51,363 (+7.3%) | June 30, 2026 |
| 9 | Dimensional Fund Advisors, Inc. | 1.76% | 610K | $43.2M | +93,428 (+18.1%) | June 30, 2026 |
| 10 | BRAIDWELL LP | 1.76% | 610K | $43.2M | +280,324 (+85.1%) | June 30, 2026 |
| 11 | The Goldman Sachs Group Inc | 1.61% | 560K | $39.6M | −306,511 (−35.4%) | June 30, 2026 |
| 12 | Citadel Advisors Llc | 1.61% | 559K | $39.6M | +497,223 (+807.2%) | June 30, 2026 |
| 13 | Eventide Asset Management, LLC | 1.58% | 549K | $38.8M | +50 (+0.0%) | June 30, 2026 |
| 14 | Wellington Management Company LLP | 1.49% | 516K | $36.5M | +29,500 (+6.1%) | June 30, 2026 |
| 15 | Emerald Advisers, LLC | 1.41% | 490K | $34.7M | +147,700 (+43.1%) | June 30, 2026 |
| 16 | UBS Group AG | 1.41% | 488K | $34.5M | −92,735 (−16.0%) | June 30, 2026 |
| 17 | Morgan Stanley - Brokerage Accounts | 1.17% | 405K | $28.7M | −289,038 (−41.6%) | June 30, 2026 |
| 18 | UBS Asset Mgmt Americas Inc | 1.15% | 398K | $28.2M | −541,273 (−57.6%) | June 30, 2026 |
| 19 | Amvescap Plc. | 1.14% | 395K | $28.0M | −642,995 (−61.9%) | June 30, 2026 |
| 20 | Citigroup Inc | 1.11% | 386K | $27.3M | +28,685 (+8.0%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 15 holders added 1.7M shares and 5 cut 1.9M.
TMDX top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | iShares Core S&P Small-Cap ETF | 5.95% | 2.1M | $146.1M | +477 (+0.0%) | September 30, 2026 |
| 2 | Vanguard MStar Total Stk Mkt Idx Invest | 3.00% | 1.0M | $73.7M | −1,425 (−0.1%) | August 31, 2026 |
| 3 | iShares Russell 2000 ETF | 2.55% | 885K | $62.6M | −10,176 (−1.1%) | September 30, 2026 |
| 4 | Vanguard Small Cap Index | 2.18% | 755K | $53.4M | +54 (+0.0%) | August 31, 2026 |
| 5 | Fidelity Small Cap Growth | 2.09% | 726K | $51.4M | — | July 31, 2026 |
| 6 | Nomura Small Cap Core I | 1.78% | 617K | $43.7M | — | August 31, 2026 |
| 7 | Fidelity Advisor New Insights I | 1.77% | 614K | $43.5M | — | August 31, 2026 |
| 8 | Fidelity VIP Contrafund Initial | 1.70% | 590K | $41.7M | — | August 31, 2026 |
| 9 | Eventide Gilead N | 1.33% | 461K | $32.6M | — | June 30, 2026 |
| 10 | Vanguard MStar Small Cap Growth Indx Inv | 1.25% | 432K | $30.6M | −3,501 (−0.8%) | August 31, 2026 |
| 11 | Fidelity VIP Mid Cap Initial | 1.11% | 384K | $27.2M | — | August 31, 2026 |
| 12 | Fidelity Small Cap Index | 1.08% | 375K | $26.5M | +3,087 (+0.8%) | July 31, 2026 |
| 13 | American Funds SMALLCAP World A | 1.08% | 374K | $26.5M | — | June 30, 2026 |
| 14 | Fidelity Small Cap Growth K6 | 1.07% | 370K | $26.2M | — | July 31, 2026 |
| 15 | Hood River Small-Cap Growth Instl | 1.05% | 365K | $25.9M | — | June 30, 2026 |
| 16 | Fidelity OTC | 1.05% | 364K | $25.7M | — | August 31, 2026 |
| 17 | Fidelity Series Opportunistic Insights | 0.99% | 344K | $24.3M | — | August 31, 2026 |
| 18 | iShares Russell 2000 Growth ETF | 0.93% | 321K | $22.7M | −406 (−0.1%) | September 30, 2026 |
| 19 | iShares S&P Small-Cap 600 Growth ETF | 0.92% | 321K | $22.7M | — | September 30, 2026 |
| 20 | State Street SPDR Port S&P 600 Sm CpETF | 0.91% | 315K | $22.3M | — | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
TMDX insider transactions
latest 14| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-03-04 | David Weill | Sell | $146.82 | 3,571 | $524,294 |
| 2026-03-04 | Gerardo Hernandez | Sell | $147.21 | 7,236 | $1.1M |
| 2026-03-04 | Stephanie Lovell | Sell | $149.62 | 1,193 | $178,497 |
| 2026-03-02 | Anil P Ranganath | Sell | $139.12 | 864 | $120,200 |
| 2026-03-02 | Gerardo Hernandez | Sell | $139.12 | 375 | $52,170 |
| 2026-03-02 | Nicholas Corcoran | Sell | $139.12 | 2,966 | $412,630 |
| 2025-12-04 | Gerardo Hernandez | Sell | $139.62 | 920 | $128,450 |
| 2025-12-03 | David Weill | Sell | $138.64 | 5,000 | $693,200 |
| 2025-11-25 | Anil P Ranganath | Sell | $145.22 | 3,000 | $435,660 |
| 2025-10-29 | Edward M Basile | Sell | $130.45 | 4,142 | $540,324 |
| 2025-06-09 | Anil P Ranganath | Sell | $139.80 | 686 | $95,903 |
| 2025-05-27 | Edward M Basile | Sell | $126.45 | 5,000 | $632,250 |
| 2025-05-23 | David Weill | Sell | $123.88 | 732 | $90,680 |
| 2025-05-09 | Edward M Basile | Sell | $115.63 | 6,000 | $693,780 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
TMDX shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns TMDX
Institutional investors own 103.0% of TransMedics's shares and insiders 3.64%. The largest holder is BlackRock Inc with 16.14% of the shares (5.6M), as of June 30, 2026. Among the top 20 institutions, 15 added shares and 5 reduced their stake in the latest filings. Short interest is 38.40% of the float, or 11.71 days of average trading volume. The share count rose 780.1% since 2017.
Related: TMDX analyst forecast, TMDX key metrics. See the TMDX stock overview for the latest quote and news.
TMDX ownership FAQ
Who owns the most TransMedics stock?
The largest shareholders of TransMedics are BlackRock Inc (16.14%), FMR Inc (14.80%), Vanguard Portfolio Management, LLC (5.58%), Vanguard Capital Management, LLC (4.32%), State Street Corp (4.10%).
What percentage of TransMedics is owned by institutions?
Institutions hold 103.0% of TransMedics's shares outstanding; insiders hold 3.64%.
Which funds own TransMedics?
The largest fund holders of TransMedics are iShares Core S&P Small-Cap ETF (5.95%), Vanguard MStar Total Stk Mkt Idx Invest (3.00%), iShares Russell 2000 ETF (2.55%), Vanguard Small Cap Index (2.18%), Fidelity Small Cap Growth (2.09%).
What is TransMedics's short interest?
8.6M shares of TransMedics were sold short, 38.40% of the float; at the average daily volume it would take 11.71 days to cover.
Are insiders buying or selling TransMedics?
Of the latest 14 reported insider transactions in TransMedics (since May 9, 2025), 0 were purchases and 14 were sales.
How many shares of TransMedics are outstanding?
TransMedics has 34.7M shares outstanding, of which 33.6M are in the public float.