ZBIO
Zenas BioPharma, Inc. · Healthcare · Market cap $2.1B
Insiders bought $7.7M net in the last 90 days ·0 sellers, 3 buyers· latest Form 4 filed May 19, 2026
Insider Buying
$30.0M
reported purchases (SEC code P)
Insider Selling
$0
reported sales (SEC code S)
Unique Insiders
7
in the rolling window
Latest filing
Jun 17, 2026
MOULDER LEON O JR
Zenas BioPharma, Inc. (ZBIO) has 18 SEC Form 4 filings (28 transaction rows) in the rolling window, disclosed by 7 distinct insiders. Most recent filing: Jun 17, 2026.
Inside the rolling window, 7 insiders at Zenas BioPharma, Inc. reported 21 open-market purchases totaling $30.0M and no open-market sales. The most active filer is Chief Executive Officer MOULDER LEON O JR with 10 filings. Insiders have net bought $11.4M over the trailing 6 months. The largest single insider purchase in this window was $3.0M by Director Fairmount Funds Management LLC on Mar 31, 2026. The most recent open-market filing is a purchase of 60,000 shares by Chief Executive Officer MOULDER LEON O JR, dated May 18, 2026, worth $1.0M.
- Industry:Biotechnology
- CEO:Leon Oliver Moulder Jr.
- Employees:167
- HQ:Waltham, MA, US
- IPO:2024-09-13
| Source | |||||||
|---|---|---|---|---|---|---|---|
| Chief Executive Officer | Purchase | 60,000 | $1.0M | May 19 | +81.0% | SEC ↗ | |
| Chief Executive Officer | Purchase | 25,000 | $451K | Apr 29 | +84.0% | SEC ↗ | |
| Chief Executive Officer | Purchase | 35,000 | $617K | Apr 29 | +84.0% | SEC ↗ | |
| Director | Purchase | 78,768 | $1.6M | Apr 2 | +50.5% | SEC ↗ | |
| Director | Purchase | 150,000 | $3.0M | Apr 1 | +58.6% | SEC ↗ | |
| Chief Executive Officer | Purchase | 20,000 | $365K | Mar 31 | +65.2% | SEC ↗ | |
| Chief Executive Officer | Purchase | 34,000 | $657K | Mar 31 | +65.2% | SEC ↗ | |
Allen Patricia LFirst filing | Director | Purchase | 15,700 | $390K | Feb 13 | +22.3% | SEC ↗ |
Allen Patricia LFirst filing | Director | Purchase | 4,160 | $110K | Feb 13 | — | SEC ↗ |
Lu HongboFirst in 4 months | Director | Purchase | 25,985 | $585K | Feb 13 | — | SEC ↗ |
| Chief Executive Officer | Purchase | 57,000 | $1.0M | Feb 3 | — | SEC ↗ | |
MOULDER LEON O JRFirst in 3 months | Chief Executive Officer | Purchase | 50,000 | $819K | Jan 9 | — | SEC ↗ |
MOULDER LEON O JRFirst in 3 months | Chief Executive Officer | Purchase | 30,000 | $489K | Jan 9 | — | SEC ↗ |
MOULDER LEON O JRFirst in 3 months | Chief Executive Officer | Purchase | 20,000 | $331K | Jan 9 | — | SEC ↗ |
SR ONE CAPITAL MANAGEMENT, LLCFirst filing | 10% Owner | Purchase | 126,315 | $2.4M | Oct 14 | — | SEC ↗ |
ENRIGHT PATRICK GFirst filing | Director | Purchase | 117,255 | $2.3M | Oct 14 | — | SEC ↗ |
Nunn Jason RaleighFirst filing | Director | Purchase | 63,158 | $1.2M | Oct 14 | — | SEC ↗ |
Lu HongboFirst filing | Director | Purchase | 58,823 | $1000K | Oct 9 | — | SEC ↗ |
Lu HongboFirst filing | Director | Purchase | 263,160 | $5.0M | Oct 9 | — | SEC ↗ |
MOULDER LEON O JRFirst filing | See Remarks | Purchase | 36,928 | $770K | Oct 9 | — | SEC ↗ |
Fairmount Funds Management LLCFirst filing | Director | Purchase | 316,219 | $6.0M | Oct 9 | — | SEC ↗ |
Frequently asked questions
How many SEC Form 4 insider filings does ZBIO have?
Zenas BioPharma, Inc. (ZBIO) has 18 SEC Form 4 filings (28 transaction rows) in the rolling 365-day window, disclosed by 7 distinct insiders. Most recent filing: Jun 17, 2026.
When was the most recent SEC Form 4 filing for ZBIO?
The most recent Form 4 filing for ZBIO on Tracefour is dated Jun 17, 2026.
Who is the most active insider at ZBIO?
The most active SEC Form 4 filer at ZBIO in the rolling window is Chief Executive Officer MOULDER LEON O JR, with 10 filings.
What is the net insider flow at ZBIO over the last 6 months?
Over the trailing 180 days, insiders at ZBIO have net bought $11.4M based on SEC Form 4 disclosures.
What was the largest insider purchase at ZBIO?
The largest single insider open-market purchase at ZBIO in the rolling window was $3.0M by Director Fairmount Funds Management LLC on 2026-03-31.
What is the total insider buy and sell value at ZBIO in the current window?
Inside the rolling window, insiders at ZBIO bought $30.0M and sold $0 based on SEC Form 4 filings.
Can I get alerts for ZBIO insider trading?
Yes. Tracefour sends a free email when a new SEC Form 4 purchase or sale is filed at Zenas BioPharma, Inc. (ZBIO). Alerts are set per company from the page itself, there is no paid tier, and each email links to the original filing on SEC EDGAR.
Related companies
Zenas BioPharma, Inc. is in the Healthcare sector.