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ZBIO · Zenas Biopharma, Inc.
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ZBIO Zenas BioPharma (ZBIO) Insider Trading, Ownership & Congress Trades

Pharma & Biotech · Pharmaceutical preparations · CIK 0001953926
Quote by TradingView
Activist 13DC-suite buying · 1Form 144 · 1
House members buying, 1 year
0
STOCK Act, US House only, disclosed up to 45 days after the trade
Funds added, last quarter
87
13F, latest reported quarter

What the filings say about ZBIO

Insiders, 180 days
+$1.0M net bought
1 buyer
Planned sales (Form 144), 90 days
$31.9M
1 notice
Activist stakes (13D), 180 days
1 filing
Largest: 5.1% of the class

Zenas BioPharma insider trades (Form 4)

Form 4 buys and sells (codes P and S). Grants, option exercises and conversions excluded.

Over the last 180 days, Zenas BioPharma, Inc. insiders bought a net $1.0M of stock across 44 Form 4 purchases and sales, with 1 insider buying. Source: SEC Form 4 filings, as of 2026-10-28.

Insider
Filed
Shares
Value
Since filing
MOULDER LEON O JR
Chief Executive Officer
BUY
2026-05-18 SEC
60,000
$1.0M
+53.0%
Context
  • 18 earlier Form 4 trades (code P or S) here by this insider (18 buys), the last on Apr 29, 2026.
  • +18.8% median (+4.5% mean) 90-day return after 17 previous buys.
  • The trade is 61.9% of the 96,928 shares held after it.
  • No other insider bought within 30 days.
  • 87 funds added in the 13F quarter to Jun 30, 2026.
Insider activity: Chief Executive Officer MOULDER LEON O JR bought about $1.0M of ZBIO on May 18, 2026; 87 funds added in the latest 13F quarter.
MOULDER LEON O JR
Chief Executive Officer
BUY
2026-04-29 SEC
35,000
$616.7K
+41.3%
Context
  • 17 earlier Form 4 trades (code P or S) here by this insider (17 buys), the last on Apr 28, 2026.
  • -0.8% median (-0.5% mean) 90-day return after 16 previous buys.
  • The trade is 2.0% of the 1,786,039 shares held after it.
  • 2 other insiders bought within 30 days.
  • 87 funds added in the 13F quarter to Jun 30, 2026.
Insider activity: Chief Executive Officer MOULDER LEON O JR bought about $616.7K of ZBIO on Apr 29, 2026; 2 other insiders bought within 30 days and 87 funds added in the latest 13F quarter.
MOULDER LEON O JR
Chief Executive Officer
BUY
2026-04-29 SECtraded 2026-04-28
25,000
$450.5K
+41.3%
Context
  • 16 earlier Form 4 trades (code P or S) here by this insider (16 buys), the last on Mar 31, 2026.
  • -20.3% median (-6.0% mean) 90-day return after 15 previous buys.
  • The trade is 1.4% of the 1,751,039 shares held after it.
  • 2 other insiders bought within 30 days.
  • 87 funds added in the 13F quarter to Jun 30, 2026.
Insider activity: Chief Executive Officer MOULDER LEON O JR bought about $450.5K of ZBIO on Apr 28, 2026; 2 other insiders bought within 30 days and 87 funds added in the latest 13F quarter.
MOULDER LEON O JR
Chief Executive Officer
BUY
2026-03-31 SEC
34,000
$656.5K
+34.1%
Context
  • 15 earlier Form 4 trades (code P or S) here by this insider (15 buys), the last on Mar 30, 2026.
  • -25.0% median (-8.6% mean) 90-day return after 14 previous buys.
  • The trade is 2.0% of the 1,726,039 shares held after it.
  • 2 other insiders bought within 30 days.
  • 87 funds added in the 13F quarter to Jun 30, 2026.
Insider activity: Chief Executive Officer MOULDER LEON O JR bought about $656.5K of ZBIO on Mar 31, 2026; 2 other insiders bought within 30 days and 87 funds added in the latest 13F quarter.
Lu Hongbo
Director
BUY
2026-03-31 SEC
75,000
$1.5M
+34.1%
Context
  • 4 earlier Form 4 trades (code P or S) here by this insider (4 buys), the last on Feb 11, 2026.
  • -20.3% median (-29.0% mean) 90-day return after 3 previous buys.
  • The trade is 17.7% of the 422,968 shares held after it.
  • 2 other insiders bought within 30 days.
  • 87 funds added in the 13F quarter to Jun 30, 2026.
Insider activity: Director Lu Hongbo bought about $1.5M of ZBIO on Mar 31, 2026; 2 other insiders bought within 30 days and 87 funds added in the latest 13F quarter.
44 transactions on record
Since filing: total return from the first close after the filing to the latest close, dividend-adjusted. Not a forecast.
Context lines are counts over the filings above and returns from our own price history, never a price level. Not investment advice.
See all insider buying · insider selling
Showing the latest few. to see 39 more transactions and use the screener and CSV export. We store only your email; there is no password.
Seven facts, ranked against the sector · Rank is not a forecast
Insiders
net +$1.0M over 180 days
more than 88% of Pharma & Biotech
Congress
no House purchase disclosed in the last 12 months
Funds
87 funds bought in last quarter
more than 63% of Pharma & Biotech
Revenue
+100.0% year over year
more than 84% of Pharma & Biotech
Margin
-3777.4% net margin
below 95% of Pharma & Biotech
Buybacks
no share repurchases reported
Short interest
27.9% of the float short (float per yahoo 2026-10-27) · 18.8 days to cover · settled 2026-10-15
more than 93% of Pharma & Biotech
The situation: each line is one rule over one dataset
MOULDER LEON O JR disclosed a 5%+ stake (5.09%) in the last six months.
What changed in the last 30 days
Nothing new filed in the last 30 days

Watch ZBIO

A free account keeps a watchlist and can send one email a day when insiders, funds or Congress file on the names in it. No password and no card.

The year, with the filings on it
Total return over 12 months. Each marker is a filing; hover or tap one for the detail.
+9.2%12M
-39%-2%+35%+73%2025-102025-122026-022026-042026-062026-082026-10 2026-03-31 · Kiselak Tomas bought $3.0M2026-03-31 · Lu Hongbo bought $1.5M2026-02-02 · MOULDER LEON O JR bought $1.0M2026-05-18 · MOULDER LEON O JR bought $1.0M2026-01-07 · MOULDER LEON O JR bought $819.0K2026-03-31 · MOULDER LEON O JR bought $656.5K2026-04-29 · MOULDER LEON O JR bought $616.7K2026-02-11 · Lu Hongbo bought $584.7K2026-01-08 · MOULDER LEON O JR bought $489.0K2026-04-28 · MOULDER LEON O JR bought $450.5K2026-03-30 · MOULDER LEON O JR bought $364.6K2026-01-09 · MOULDER LEON O JR bought $331.0K2026-02-12 · Allen Patricia L bought $138.7K2026-02-12 · Allen Patricia L bought $132.5K2026-02-12 · Allen Patricia L bought $118.8K2026-02-13 · Allen Patricia L bought $109.7K2026-03-31 · Lu Hongbo bought $70.2K2026-05-05 · MOULDER LEON O JR filed a 5%+ stake (5.09%)2026-05-05 · Tellus BioVentures, LLC filed a 5%+ stake (2.9%)2026-05-05 · Leon O. Moulder, Jr. Revocable Trust U/A dtd 9/9/2008 filed a 5%+ stake (0.1%)2026-08-19 · Zebra Aggregator, LP filed to sell $31.9M
Insider buy13D/G stakeForm 144 (planned sale)
Indexed to 100, dividend-adjusted, not a price chart. When a name files heavily, the largest trades are drawn first.

Who owns ZBIO: institutional holders (13F)

13F holdings, latest reported quarter
FMR LLC
9,506,701 sh
$241.3M
SR One Capital Management, LP
5,037,854 sh
$127.9M
NEA Management Company, LLC
4,023,219 sh
$102.1M
ENAVATE SCIENCES GP, LLC
3,919,159 sh
$99.5M
FEDERATED HERMES, INC.
3,116,805 sh
$79.1M

Congress trades in ZBIO

No Congress trades reported
No House member has disclosed a trade in this stock. See what Congress is buying.

Activist and 5% holders (13D/13G)

13D: intends to influence · 13G: passive
MOULDER LEON O JR
Activist 13D · 2026-05-05
5.09%
Tellus BioVentures, LLC
Activist 13D · 2026-05-05
2.9%
Leon O. Moulder, Jr. Revocable Trust U/A dtd 9/9/2008
Activist 13D · 2026-05-05
0.1%

ZBIO planned insider sales (Form 144)

Notice of intent to sell, filed before any sale
Zebra Aggregator, LP
Filed 2026-08-19
$31.9M

ZBIO mutual fund holders (N-PORT)

Funds ranked by the share of their own portfolio in this stock (N-PORT).
Virtus Biotech Clinical Trials Etf
$493.5K position · as of 2026-07-31
1.1%
Federated Hermes Kaufmann Small Cap Fund
$28.2M position · as of 2026-07-31
1.0%
Federated Hermes Kaufmann Fund
$41.8M position · as of 2026-07-31
0.8%
Meridian Contrarian Fund
$5.7M position · as of 2026-06-30
0.8%
Meridian Small Cap Growth Fund
$2.1M position · as of 2026-06-30
0.8%
Fidelity Advisor Biotechnology Fund
$15.5M position · as of 2026-07-31
0.7%
SEC N-PORT, monthly, about 60 days late · funds ≥ $10M · % is the share of the fund's own portfolio
Live price
Daily candles from TradingView, under their licence. No filings marked.
Why this name is on the desk
An activist crossed the 5% line with declared intent.
The record shows a net $1.0M bought by insiders over 180 days, 87 funds added last quarter, $31.9M in planned Form 144 sales. Each figure is a federal filing, dated the day it went public.
Backtest this pattern Open the screener
Same sector, ranked by filing activity
Sector by SEC SIC code
UTHRCPIXMRNAREGNLLYALNYMDGLCITRDNAVRTXNUVLTWST

ZBIO financials

Revenue growth
+100.0%
XBRL, annual
Net margin
-3777.4%
Ratios from the company's XBRL filings, latest filings
Revenue, TTM
n/a
fewer than four consecutive quarters of revenue filed
Net margin, TTM
n/a
needs four consecutive quarters of both revenue and net income
Free cash flow, TTM
-$226.0M
operating cash flow minus capex, 2025-07-01 to 2026-06-30
Debt to equity
0.32x
long-term debt only, 2025-12-31 (6 months older than the period end); equity 2026-06-30
Cash flow to debt
-2.87x
TTM operating cash flow over long-term debt only, 2025-12-31 (6 months older than the period end)
Return on equity
-199.0%
TTM net income over average of 2025-06-30 and 2026-06-30
Return on assets
-97.4%
TTM net income over average of 2025-06-30 and 2026-06-30
Return on invested capital
n/a
tax provision or pre-tax income not filed for the four quarters
Return on capital employed
-108.6%
operating income (EBIT proxy) over average of 2025-06-30 and 2026-06-30 minus current liabilities
P/E, trailing
n/a
trailing loss, a multiple of a loss is not meaningful
Enterprise value
$1.7B
market value at close 2026-10-27 on 2026-07-31 shares, plus long-term debt only, 2025-12-31 (6 months older than the period end), minus cash 2026-06-30
FCF yield
-12.7%
TTM free cash flow over market value at close 2026-10-27
PEG, trailing
n/a
trailing loss, a multiple of a loss is not meaningful
Price as of 2026-10-27. Hover or tap a tile for its yearly and quarterly history.
Method
TTM is four consecutive fiscal quarters; Q4 is the year minus nine months when not filed. Returns use the average of opening and closing balances. EBIT is approximated by operating income. PEG uses trailing EPS growth.
Fundamentals
Annual figures from XBRL filings. Pick a past date to see them as known then.
2025-122024-122023-12
Revenue$10.0M$5.0M$50.0M
Operating income-$383.1M-$163.9M-$37.1M
Net income-$377.7M-$157.0M-$37.1M
EPS (diluted)-8.44-11.89-24.25
Operating cash flow-$172.3M-$119.7M-$30.5M
Cash$110.6M$319.7M$56.9M
Long-term debt$78.6Mn/an/a
SEC XBRL, fiscal years, as known on 2026-10-28

ZBIO Stock Sonar score 6/7 axes

Find similar shapesCompare

ZBIO ranks highest on growth (84th percentile) and insider conviction (72nd), and lowest on risk and compliance (16th), among Pharma & Biotech peers.

ProfitHealthGrowthInsidersInstitutionsRisk
Profitability
22
Inputs
  • Return on equity-199.0% · 17 pct, sector of 545
  • Return on assets-97.4% · 25 pct, sector of 691
  • Return on invested capitaltax provision or pre-tax income not filed for the four quarters
  • Return on capital employed-108.6% · 23 pct, sector of 576
Financial health
38
Inputs
  • Debt to equity0.32x · 39 pct, sector of 352
  • Cash flow to debt-2.87x · 38 pct, sector of 371
Growth
84
Inputs
  • Revenue growth, YoY+100.0% · 84 pct, sector of 505
  • Backlog growth, YoYno backlog line filed, or no year-earlier backlog
Insider conviction
72
Inputs
  • Net Form 4 buying (codes P and S), 180d$1.0M · 87 pct, sector of 429
  • Insider buyers, 180d1 · 56 pct, sector of 438
Institutional and government
63
Inputs
  • Funds adding, latest quarter87 · 63 pct, sector of 698
  • Congress net buyers, 365dno Congress trades in 365 days
  • Federal contracts, 180dno federal contracts in 180 days
  • Lobbying spend, 4 quartersno lobbying filings in the last four quarters
Risk and compliance
16
Inputs
  • Short interest, % of float+27.9% · 5 pct, sector of 816
  • Recalls per $1B revenue, 3yrevenue under $50M or not filed, so a count cannot be scaled to size
  • EPA cases per $1B revenue, 5yrevenue under $50M or not filed, so a count cannot be scaled to size
  • New text in Risk Factors, latest 10-K+15.6% · 28 pct, sector of 511
1 not measured: US patents
  • US patents needs 1 of 2 inputs, 0 present: patent data not loaded yet

6 of 7 axes scored. Each is a percentile against sector peers (all companies when the sector is thin); higher is better. An unscored axis is unmeasured, not low. How it is scored

ZBIO filings, in plain words

Are Zenas BioPharma insiders buying or selling ZBIO?

In the 180 days to 2026-10-28, Zenas BioPharma insiders were net buyers, a net $1.0M across purchases and sales reported on Form 4, by 1 buyer.

Are there planned insider sales of ZBIO?

Yes. 1 Form 144 notice of planned insider sales was filed in the 90 days to 2026-10-28, covering $31.9M of stock; the latest, by Zebra Aggregator, LP, was filed 2026-08-19.

Read the full summary

In the 180 days to 2026-10-28, Zenas BioPharma insiders were net buyers of ZBIO, a net $1.0M across purchases and sales reported on Form 4 by 1 buyer. Insiders filed 1 Form 144 notice of intent to sell in the 90 days to 2026-10-28, covering $31.9M of stock. 1 activist Schedule 13D filing in the last 180 days declared an intent to influence the company, the largest for 5.1% of the class. Each figure is counted from SEC and House filings as of 2026-10-28, dated the day the filing was made public.

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