Zenas BioPharma, Inc. (ZBIO) Ownership
ZBIO ownership summary
as of October 18, 2026- Institutions
- 101.5% of shares outstanding
- Insiders
- 19.75% of shares outstanding
- Shares outstanding
- 65.2M
- Float
- 45.0M shares available to trade
- Short interest
- 26.90% 11.9M shares short
- Days to cover
- 18.11 short interest up 0.6% vs prior month
- Institutions 101.50%
- Insiders 19.75%
ZBIO top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | FMR Inc | 14.59% | 9.5M | $236.1M | +424,701 (+4.7%) | June 30, 2026 |
| 2 | SR ONE CAPITAL MANAGEMENT, LP | 7.73% | 5.0M | $125.1M | — | June 30, 2026 |
| 3 | NEA Management Company, LLC | 6.17% | 4.0M | $99.9M | — | June 30, 2026 |
| 4 | Enavate Sciences GP, LLC | 6.01% | 3.9M | $97.4M | — | June 30, 2026 |
| 5 | Federated Hermes Inc | 4.78% | 3.1M | $77.4M | −10,226 (−0.3%) | June 30, 2026 |
| 6 | BlackRock Inc | 4.12% | 2.7M | $66.7M | +648,677 (+31.8%) | June 30, 2026 |
| 7 | Capital Research & Mgmt Co - Division 3 | 3.84% | 2.5M | $62.2M | +68,912 (+2.8%) | June 30, 2026 |
| 8 | Polar Capital Holdings PLC | 3.70% | 2.4M | $59.9M | −135,672 (−5.3%) | June 30, 2026 |
| 9 | Royalty Pharma Sub-Manager, LLC | 3.66% | 2.4M | $59.3M | +2.4M (0.0%) | June 30, 2026 |
| 10 | Fairmount Funds Management LLC | 3.62% | 2.4M | $58.6M | — | June 30, 2026 |
| 11 | State Street Corp | 3.15% | 2.1M | $51.0M | +584,177 (+39.7%) | June 30, 2026 |
| 12 | NVP Associates LLC | 2.82% | 1.8M | $45.7M | — | June 30, 2026 |
| 13 | Wellington Management Company LLP | 2.45% | 1.6M | $39.6M | +347,766 (+27.9%) | June 30, 2026 |
| 14 | Vanguard Capital Management, LLC | 2.08% | 1.4M | $33.7M | +109,473 (+8.8%) | June 30, 2026 |
| 15 | Bank of America Corp | 1.89% | 1.2M | $30.6M | +842,812 (+217.0%) | June 30, 2026 |
| 16 | T. Rowe Price Associates, Inc. | 1.88% | 1.2M | $30.5M | +869,662 (+243.4%) | June 30, 2026 |
| 17 | AllianceBernstein L.P. | 1.69% | 1.1M | $27.4M | +206,067 (+23.0%) | June 30, 2026 |
| 18 | Geode Capital Management, LLC | 1.35% | 883K | $21.9M | +226,869 (+34.6%) | June 30, 2026 |
| 19 | Two Sigma Investments LLC | 1.25% | 815K | $20.2M | +540,094 (+196.4%) | June 30, 2026 |
| 20 | EcoR1 Capital, LLC | 1.21% | 790K | $19.6M | — | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 12 holders added 7.3M shares and 2 cut 146K.
ZBIO top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | American Funds SMALLCAP World A | 3.73% | 2.4M | $60.5M | — | June 30, 2026 |
| 2 | Polar Capital Biotech S Inc | 3.51% | 2.3M | $56.8M | — | August 31, 2026 |
| 3 | Federated Hermes Kaufmann R | 2.80% | 1.8M | $45.3M | — | June 30, 2026 |
| 4 | Federated Hermes Kaufmann Small Cap A | 1.92% | 1.3M | $31.1M | — | June 30, 2026 |
| 5 | Fidelity Select Health Care | 1.90% | 1.2M | $30.8M | +160,865 (+14.9%) | August 31, 2026 |
| 6 | Fidelity Small Cap Growth | 1.76% | 1.1M | $28.5M | — | July 31, 2026 |
| 7 | Strategic Advisers Fidelity US TtlStk | 1.63% | 1.1M | $26.4M | +13,592 (+1.3%) | August 31, 2026 |
| 8 | State Street® SPDR® S&P® Biotech ETF | 1.60% | 1.0M | $25.9M | −19,950 (−1.9%) | September 30, 2026 |
| 9 | iShares Russell 2000 ETF | 1.43% | 932K | $23.1M | −10,752 (−1.1%) | September 30, 2026 |
| 10 | Vanguard MStar Total Stk Mkt Idx Invest | 1.37% | 891K | $22.1M | — | August 31, 2026 |
| 11 | Fidelity Stock Selector Small Cap | 1.02% | 663K | $16.5M | +46,081 (+7.5%) | July 31, 2026 |
| 12 | Fidelity Select Biotechnology | 0.99% | 644K | $16.0M | +263,137 (+69.2%) | August 31, 2026 |
| 13 | Fidelity Small Cap Growth K6 | 0.94% | 611K | $15.2M | — | July 31, 2026 |
| 14 | Fidelity Advisor Biotechnology I | 0.89% | 578K | $14.4M | +86,234 (+17.5%) | August 31, 2026 |
| 15 | Fidelity Advisor Health Care I | 0.77% | 500K | $12.4M | — | August 31, 2026 |
| 16 | AB Small Cap Growth A | 0.72% | 467K | $11.6M | +13,460 (+3.0%) | August 31, 2026 |
| 17 | T. Rowe Price New Horizons | 0.65% | 425K | $10.5M | −17,355 (−3.9%) | August 31, 2026 |
| 18 | Fidelity Series Small Cap Opps | 0.60% | 391K | $9.7M | — | July 31, 2026 |
| 19 | T. Rowe Price Integrated US Sm Gr Eq | 0.59% | 385K | $9.6M | — | August 31, 2026 |
| 20 | iShares Russell 2000 Growth ETF | 0.52% | 336K | $8.4M | −426 (−0.1%) | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
ZBIO insider transactions
latest 16| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-03-31 | Fairmount Funds Management Llc | Buy | $20.00 | 150,000 | $3.0M |
| 2026-03-31 | Hongbo Lu | Buy | $18.63 | 3,768 | $70,198 |
| 2026-02-13 | Patricia L Allen | Buy | $26.36 | 4,160 | $109,658 |
| 2026-02-12 | Patricia L Allen | Buy | $24.85 | 15,700 | $390,145 |
| 2026-02-11 | Hongbo Lu | Buy | $22.50 | 25,985 | $584,662 |
| 2026-02-02 | Leon O Moulder Jr | Buy | $17.96 | 57,000 | $1.0M |
| 2026-01-09 | Leon O Moulder Jr | Buy | $16.55 | 20,000 | $331,000 |
| 2026-01-08 | Leon O Moulder Jr | Buy | $16.30 | 30,000 | $489,000 |
| 2026-01-07 | Leon O Moulder Jr | Buy | $16.38 | 50,000 | $819,000 |
| 2025-10-09 | Jason Raleigh Nunn | Buy | $19.00 | 63,158 | $1.2M |
| 2025-10-09 | Patrick G Enright | Buy | $20.85 | 11,990 | $249,992 |
| 2025-10-09 | Patrick G Enright | Buy | $19.00 | 105,265 | $2.0M |
| 2025-10-09 | Sr One Capital Management, Llc | Buy | $19.00 | 126,315 | $2.4M |
| 2025-10-07 | Fairmount Funds Management Llc | Buy | $19.00 | 316,219 | $6.0M |
| 2025-10-07 | Hongbo Lu | Buy | $19.00 | 263,160 | $5.0M |
| 2025-10-07 | Leon O Moulder Jr | Buy | $20.85 | 36,928 | $769,949 |
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.
ZBIO shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns ZBIO
Institutional investors own 101.5% of Zenas BioPharma's shares and insiders 19.75%. The largest holder is FMR Inc with 14.59% of the shares (9.5M), as of June 30, 2026. Among the top 20 institutions, 12 added shares and 2 reduced their stake in the latest filings. Short interest is 26.90% of the float, or 18.11 days of average trading volume. The share count rose 21.3% since 2022.
Related: ZBIO analyst forecast, ZBIO key metrics. See the ZBIO stock overview for the latest quote and news.
ZBIO ownership FAQ
Who owns the most Zenas BioPharma stock?
The largest shareholders of Zenas BioPharma are FMR Inc (14.59%), SR ONE CAPITAL MANAGEMENT, LP (7.73%), NEA Management Company, LLC (6.17%), Enavate Sciences GP, LLC (6.01%), Federated Hermes Inc (4.78%).
What percentage of Zenas BioPharma is owned by institutions?
Institutions hold 101.5% of Zenas BioPharma's shares outstanding; insiders hold 19.75%.
Which funds own Zenas BioPharma?
The largest fund holders of Zenas BioPharma are American Funds SMALLCAP World A (3.73%), Polar Capital Biotech S Inc (3.51%), Federated Hermes Kaufmann R (2.80%), Federated Hermes Kaufmann Small Cap A (1.92%), Fidelity Select Health Care (1.90%).
What is Zenas BioPharma's short interest?
11.9M shares of Zenas BioPharma were sold short, 26.90% of the float; at the average daily volume it would take 18.11 days to cover.
Are insiders buying or selling Zenas BioPharma?
Of the latest 16 reported insider transactions in Zenas BioPharma (since October 7, 2025), 16 were purchases and 0 were sales.
How many shares of Zenas BioPharma are outstanding?
Zenas BioPharma has 65.2M shares outstanding, of which 45.0M are in the public float.