Zenas BioPharma, Inc. (ZBIO) Insider Trading
Over the last 3 months, ZBIO insiders made 8 open-market buys and 0 sales, a net purchase of $7.7M (SEC Form 4). Multiple insiders bought within days of each other (cluster buying). Over the last 6 months, 101 institutions increased and 41 reduced their position (13F).
Insider Activity
Sentiment
100/100
Buys (3m)
8
Sells (3m)
0
Net (3m)
$7.7M
Insiders buyingCluster buying
Insider trades by month Buys Sells
Oct
Jan
Feb
Mar
Apr
May
Context3-month price -32.6%Institutions accumulating (13F)
| Date | Insider | Type | Shares | Price |
|---|---|---|---|---|
| May 18, 2026 | MOULDER LEON O JRdirector, officer: Chief Executive Officer | Buy | 60,000 | $16.88 |
| Apr 29, 2026 | MOULDER LEON O JRdirector, officer: Chief Executive Officer | Buy | 25,000 | $18.02 |
| Apr 29, 2026 | MOULDER LEON O JRdirector, officer: Chief Executive Officer | Buy | 35,000 | $17.62 |
| Apr 2, 2026 | Lu Hongbodirector | Buy | 3,768 | $18.63 |
| Apr 1, 2026 | Fairmount Funds Management LLCdirector | Buy | 150,000 | $20.00 |
| Mar 31, 2026 | Lu Hongbodirector | Buy | 75,000 | $20.00 |
| Mar 31, 2026 | MOULDER LEON O JRdirector, officer: Chief Executive Officer | Buy | 34,000 | $19.31 |
| Mar 31, 2026 | MOULDER LEON O JRdirector, officer: Chief Executive Officer | Buy | 20,000 | $18.23 |
| Feb 13, 2026 | Allen Patricia Ldirector | Buy | 5,000 | $26.50 |
| Feb 13, 2026 | Allen Patricia Ldirector | Buy | 4,160 | $26.36 |
| Feb 13, 2026 | Lu Hongbodirector | Buy | 25,985 | $22.50 |
| Feb 13, 2026 | Allen Patricia Ldirector | Buy | 5,700 | $24.34 |
| Feb 3, 2026 | MOULDER LEON O JRdirector, officer: Chief Executive Officer | Buy | 57,000 | $17.96 |
| Jan 9, 2026 | MOULDER LEON O JRdirector, officer: Chief Executive Officer | Buy | 20,000 | $16.55 |
| Jan 9, 2026 | MOULDER LEON O JRdirector, officer: Chief Executive Officer | Buy | 30,000 | $16.30 |
| Jan 9, 2026 | MOULDER LEON O JRdirector, officer: Chief Executive Officer | Buy | 50,000 | $16.38 |
| Oct 14, 2025 | ENRIGHT PATRICK Gdirector | Buy | 11,990 | $20.85 |
| Oct 14, 2025 | Nunn Jason Raleighdirector | Buy | 63,158 | $19.00 |
| Oct 14, 2025 | SR ONE CAPITAL MANAGEMENT, LLC10 percent owner | Buy | 63,157 | $19.00 |
| Oct 14, 2025 | SR ONE CAPITAL MANAGEMENT, LLC10 percent owner | Buy | 63,158 | $19.00 |
| Oct 14, 2025 | ENRIGHT PATRICK Gdirector | Buy | 105,265 | $19.00 |
| Oct 9, 2025 | Lu Hongbodirector | Buy | 58,823 | $17.00 |
| Oct 9, 2025 | Lu Hongbodirector | Buy | 263,160 | $19.00 |
| Oct 9, 2025 | Fairmount Funds Management LLCdirector | Buy | 316,219 | $19.00 |
| Oct 9, 2025 | MOULDER LEON O JRdirector, officer: See Remarks | Buy | 36,928 | $20.85 |
| Jun 12, 2025 | ORLOFF JOHN Jdirector | Grant | 18,500 | $11.94 |
| Jun 12, 2025 | Lu Hongbodirector | Grant | 18,500 | $11.94 |
| Jun 12, 2025 | MOULDER LEON O JRdirector, officer: See Remarks | Grant | 400,000 | $11.94 |
| Jun 12, 2025 | Oliveira Orlandoofficer: See Remarks | Grant | 100,000 | $11.94 |
| Jun 12, 2025 | Fox Jennifer A.officer: See Remarks | Grant | 150,000 | $11.94 |
Source: ZBIO SEC Form 4 filings, latest May 18, 2026. For informational purposes only — not investment advice.
Institutional activity (13F)
How institutions changed their ZBIO positions over the last 6 months (SEC Form 13F).
Increased
101
New positions
99
Reduced
41
Sold out
42
Largest moves
| Institution | Action | Shares | Filed |
|---|---|---|---|
| FMR LLC | Increased | 9.1M | May 15, 2026 |
| FMR LLC | Increased | 7.7M | Feb 17, 2026 |
| SR ONE CAPITAL MANAGEMENT, LP | Increased | 5.0M | Feb 12, 2026 |
| SR ONE CAPITAL MANAGEMENT, LP | Unchanged | 5.0M | May 14, 2026 |
| NEA MANAGEMENT COMPANY, LLC | Increased | 4.0M | May 15, 2026 |
| ENAVATE SCIENCES GP, LLC | Increased | 3.9M | Feb 17, 2026 |
| ENAVATE SCIENCES GP, LLC | Unchanged | 3.9M | May 15, 2026 |
| NEA MANAGEMENT COMPANY, LLC | Increased | 3.5M | Feb 17, 2026 |
| FEDERATED HERMES, INC. | Increased | 3.1M | May 11, 2026 |
| FEDERATED HERMES, INC. | Increased | 2.7M | Feb 12, 2026 |
| POLAR CAPITAL HOLDINGS PLC | Increased | 2.5M | May 15, 2026 |
| CAPITAL INTERNATIONAL INVESTORS | New Position | 2.4M | May 13, 2026 |
| FAIRMOUNT FUNDS MANAGEMENT LLC | Increased | 2.4M | May 15, 2026 |
| FAIRMOUNT FUNDS MANAGEMENT LLC | Increased | 2.2M | Feb 17, 2026 |
| BLACKROCK, INC. | Increased | 2.0M | May 13, 2026 |
Source: SEC Form 13F filings. For informational purposes only — not investment advice.