ZBIO
Moulder Leon O Jr, ZBIO's CEO, spent $1.01M of their own money on 60,000 shares at $17, growing their stake 162%.
+$1.01M
60,000 sh @ $17
ZBIO
Zenas BioPharma, Inc.
SEC CIK 1953926
$17.76
−9.9% · 90 days
90-day buys
$7.67M
8 open-market
90-day sells
$0
0 open-market
Net insider flow
+$7.67M
Net buying
Filings shown
26
Most recent
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At a glance
Over the last 90 days, insiders at ZBIO have bought a net $7.67M of stock (8 open-market buys vs 0 sells).
Largest recent trade: Fairmount Funds Management Llc, ZBIO's Director, spent $6.01M of their own money on 316,219 shares at $19, growing their stake 17%.
Most active filer: Moulder Leon O Jr, with 10 transactions among the recent filings shown.
Insider transaction history
Form 4 filings for ZBIO, newest firstZBIO
Moulder Leon O Jr, ZBIO's CEO, spent $616.7K of their own money on 35,000 shares at $18, growing their stake 2%.
+$616.7K
35,000 sh @ $18
ZBIO
Moulder Leon O Jr, ZBIO's CEO, spent $450.5K of their own money on 25,000 shares at $18, growing their stake 1%.
+$450.5K
25,000 sh @ $18
ZBIO
Lu Hongbo, ZBIO's Director, spent $70.2K of their own money on 3,768 shares at $19, growing their stake 1%.
+$70.2K
3,768 sh @ $19
ZBIO
Fairmount Funds Management Llc, ZBIO's Director, spent $3M of their own money on 150,000 shares at $20, growing their stake 7%.
+$3M
150,000 sh @ $20
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ZBIO
Moulder Leon O Jr, ZBIO's CEO, spent $656.5K of their own money on 34,000 shares at $19, growing their stake 2%.
+$656.5K
34,000 sh @ $19
ZBIO
Lu Hongbo, ZBIO's Director, spent $1.5M of their own money on 75,000 shares at $20, growing their stake 22%.
+$1.5M
75,000 sh @ $20
ZBIO
Moulder Leon O Jr, ZBIO's CEO, spent $364.6K of their own money on 20,000 shares at $18, growing their stake 1%.
+$364.6K
20,000 sh @ $18
ZBIO
Allen Patricia L, ZBIO's Director, spent $109.7K of their own money on 4,160 shares at $26, growing their stake 26%.
+$109.7K
4,160 sh @ $26
ZBIO
Allen Patricia L, ZBIO's Director, spent $118.9K of their own money on 5,000 shares at $24, opening a brand-new position.
+$118.9K
5,000 sh @ $24
ZBIO
Allen Patricia L, ZBIO's Director, spent $138.7K of their own money on 5,700 shares at $24, growing their stake 114%.
+$138.7K
5,700 sh @ $24
ZBIO
Allen Patricia L, ZBIO's Director, spent $132.5K of their own money on 5,000 shares at $27, growing their stake 47%.
+$132.5K
5,000 sh @ $27
ZBIO
Lu Hongbo, ZBIO's Director, spent $584.7K of their own money on 25,985 shares at $23, growing their stake 8%.
+$584.7K
25,985 sh @ $23
ZBIO
Moulder Leon O Jr, ZBIO's CEO, spent $1.02M of their own money on 57,000 shares at $18, growing their stake 16%.
+$1.02M
57,000 sh @ $18
ZBIO
Moulder Leon O Jr, ZBIO's CEO, spent $331K of their own money on 20,000 shares at $17, growing their stake 6%.
+$331K
20,000 sh @ $17
ZBIO
Moulder Leon O Jr, ZBIO's CEO, spent $489K of their own money on 30,000 shares at $16, growing their stake 9%.
+$489K
30,000 sh @ $16
ZBIO
Moulder Leon O Jr, ZBIO's CEO, spent $819K of their own money on 50,000 shares at $16, growing their stake 19%.
+$819K
50,000 sh @ $16
ZBIO
Nunn Jason Raleigh, ZBIO's Director, spent $1.2M of their own money on 63,158 shares at $19, growing their stake 6%.
+$1.2M
63,158 sh @ $19
ZBIO
Sr One Capital Management, Llc, ZBIO's 10% owner, spent $1.2M of their own money on 63,158 shares at $19, growing their stake 6%.
+$1.2M
63,158 sh @ $19
ZBIO
Sr One Capital Management, Llc, ZBIO's 10% owner, spent $1.2M of their own money on 63,157 shares at $19, growing their stake 3%.
+$1.2M
63,157 sh @ $19
ZBIO
Enright Patrick G, ZBIO's Director, spent $2M of their own money on 105,265 shares at $19, growing their stake 6%.
+$2M
105,265 sh @ $19
ZBIO
Enright Patrick G, ZBIO's Director, spent $250K of their own money on 11,990 shares at $21, opening a brand-new position.
+$250K
11,990 sh @ $21
ZBIO
Moulder Leon O Jr, ZBIO's Director, spent $769.9K of their own money on 36,928 shares at $21, opening a brand-new position.
+$769.9K
36,928 sh @ $21
ZBIO
Fairmount Funds Management Llc, ZBIO's Director, spent $6.01M of their own money on 316,219 shares at $19, growing their stake 17%.
+$6.01M
316,219 sh @ $19
ZBIO
Lu Hongbo, ZBIO's Director, spent $5M of their own money on 263,160 shares at $19, growing their stake 447%.
+$5M
263,160 sh @ $19
ZBIO
Lu Hongbo, ZBIO's Director, spent $1,000K of their own money on 58,823 shares at $17, opening a brand-new position.
+$1,000K
58,823 sh @ $17
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About ZBIO insider activity
This page tracks every recent Form 4 filed for Zenas BioPharma, Inc. with the U.S. Securities and Exchange Commission. Form 4 is the disclosure that company insiders — officers, directors, and holders of more than 10% of the stock — must file within two business days of buying or selling shares.
The summary above nets open-market purchases against open-market sales over the trailing 90 days. Open-market trades (codes P and S) tend to carry the most signal because they reflect a deliberate choice to put money in or take it out, as opposed to routine grants, option exercises, or tax-withholding events. Use the badges on each row to tell them apart, and always confirm details against the original filing before drawing conclusions.
Frequently asked questions
How often is ZBIO insider data updated?
Continuously. We read from SEC EDGAR, so new Form 4 filings for Zenas BioPharma, Inc. usually appear here within minutes of being accepted by the SEC.
What does "net insider flow" mean?
It is the total dollar value of open-market insider purchases minus open-market sales over the last 90 days. A positive number (green) means insiders bought more than they sold; a negative number (red) means the reverse.
Why do some rows show grants or option exercises instead of buys?
Insiders receive stock through compensation as well as buying it outright. Form 4 captures all of these. We label each transaction by its SEC code so you can focus on open-market activity if you prefer.
Is this investment advice?
No. InsiderSource presents public filing data for informational purposes only. Insider activity is one of many factors to consider and is never a recommendation to buy or sell.