STOCK TITAN

Zenas BioPharma (ZBIO) CEO adds 60,000 shares in open-market buy

Filing Impact
(Very High)
Filing Sentiment
(Positive)
Form Type
4

Rhea-AI Filing Summary

Zenas BioPharma, Inc. Chief Executive Officer Leon O. Moulder Jr. reported an open-market purchase of 60,000 shares of Common Stock. The shares were bought indirectly through an entity associated with him at a weighted average price of $16.88 per share, with individual trade prices ranging from $16.59 to $16.97. After this transaction, that indirect account held 96,928 shares. As of the same date, he also reported 423,155 shares held directly and 1,786,039 additional shares held indirectly through entities where he may be deemed to have voting and dispositive power, while disclaiming beneficial ownership beyond his pecuniary interest.

Positive

  • None.

Negative

  • None.
Insider MOULDER LEON O JR
Role Chief Executive Officer
Bought 60,000 shs ($1.01M)
Type Security Shares Price Value
Purchase Common Stock 60,000 $16.88 $1.01M
holding Common Stock -- -- --
holding Common Stock -- -- --
Holdings After Transaction: Common Stock — 96,928 shares (Indirect, See Footnote); Common Stock — 423,155 shares (Direct, null)
Footnotes (1)
  1. The price reported is a weighted average price. These shares were purchased in multiple transactions ranging from $16.59 to $16.97, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range. The reporting person is a Trustee of the Leon O. Moulder, Jr. Revocable Trust U/A dtd 9/9/2008 (the "Trust") and may be deemed to have voting and dispositive power over the shares held by the Trust. The reporting person is the Issuer's chief executive officer and Chairman of its board of directors. The reporting person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein. Leon O. Moulder, Jr. is the Managing Member of Tellus BioVentures LLC ("Tellus") and may be deemed to have sole voting and dispositive power over the shares held by Tellus. Mr. Moulder is the Issuer's chief executive officer and Chairman of its board of directors. The reporting person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.
Open-market purchase 60,000 shares Common Stock bought indirectly on 2026-05-18
Weighted average purchase price $16.88/share Open-market trades ranged from $16.59 to $16.97
Indirect holdings after purchase (account) 96,928 shares Indirect Common Stock position in the purchasing account
Direct holdings 423,155 shares Common Stock held directly as of 2026-05-18
Other indirect holdings 1,786,039 shares Common Stock held indirectly through related entities
open-market purchase financial
"Purchase in open market or private transaction"
An open-market purchase is when an investor or a company buys shares on a public stock exchange at the going market price, rather than through a private deal. It matters to investors because these purchases change how many shares are available, can push the stock price up or signal confidence from large buyers, and often affect per-share metrics like earnings—think of it like someone buying lots of apples off a grocery shelf, reducing supply and potentially raising the price.
weighted average price financial
"The price reported is a weighted average price."
Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.
voting and dispositive power financial
"may be deemed to have voting and dispositive power over the shares"
beneficial ownership financial
"The reporting person disclaims beneficial ownership of such securities"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
pecuniary interest financial
"except to the extent of his pecuniary interest therein."
SEC Form 4
FORM 4UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number:3235-0287
Estimated average burden
hours per response:0.5
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
1. Name and Address of Reporting Person*
MOULDER LEON O JR

(Last)(First)(Middle)
C/O ZENAS BIOPHARMA, INC.
852 WINTER STREET, SUITE 250

(Street)
WALTHAM MASSACHUSETTS 02451

(City)(State)(Zip)

UNITED STATES

(Country)
2. Issuer Name and Ticker or Trading Symbol
Zenas BioPharma, Inc. [ ZBIO ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
XDirector10% Owner
XOfficer (give title below)Other (specify below)
Chief Executive Officer
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
05/18/2026
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year)2A. Deemed Execution Date, if any (Month/Day/Year)3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeVAmount(A) or (D)Price
Common Stock05/18/2026P60,000A$16.88(1)96,928ISee Footnote(2)
Common Stock1,786,039ISee Footnote(3)
Common Stock423,155D
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year)3A. Deemed Execution Date, if any (Month/Day/Year)4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year)7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Explanation of Responses:
1. The price reported is a weighted average price. These shares were purchased in multiple transactions ranging from $16.59 to $16.97, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range.
2. The reporting person is a Trustee of the Leon O. Moulder, Jr. Revocable Trust U/A dtd 9/9/2008 (the "Trust") and may be deemed to have voting and dispositive power over the shares held by the Trust. The reporting person is the Issuer's chief executive officer and Chairman of its board of directors. The reporting person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.
3. Leon O. Moulder, Jr. is the Managing Member of Tellus BioVentures LLC ("Tellus") and may be deemed to have sole voting and dispositive power over the shares held by Tellus. Mr. Moulder is the Issuer's chief executive officer and Chairman of its board of directors. The reporting person disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.
By: /s/ Chase Jayasekera, Attorney-in-Fact05/18/2026
** Signature of Reporting PersonDate
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did Zenas BioPharma (ZBIO) report for Leon O. Moulder Jr.?

Leon O. Moulder Jr. reported buying 60,000 shares of Zenas BioPharma Common Stock in an open-market transaction. The shares were acquired indirectly through an associated entity, increasing that entity’s holdings and reflecting additional exposure to the company’s equity.

At what price did the Zenas BioPharma CEO buy the 60,000 ZBIO shares?

The 60,000 shares were purchased at a weighted average price of $16.88 per share. According to the disclosure, individual trades occurred at prices ranging from $16.59 to $16.97, with full breakdowns available on request from the issuer or regulators.

How many Zenas BioPharma shares does Leon O. Moulder Jr. hold directly after this Form 4?

After the reported transactions, Leon O. Moulder Jr. held 423,155 shares of Zenas BioPharma Common Stock directly. This direct position is separate from his indirect holdings through trusts or entities where he may share voting and dispositive power.

What are the indirect ZBIO share holdings reported by Leon O. Moulder Jr.?

The filing shows 96,928 shares indirectly held in the account that purchased the 60,000 shares, plus 1,786,039 additional shares indirectly held. These indirect positions are through entities such as a revocable trust and Tellus BioVentures LLC, subject to beneficial ownership disclaimers.

How does the Form 4 describe Leon O. Moulder Jr.’s beneficial ownership of indirect ZBIO shares?

The disclosure states he may be deemed to have voting and dispositive power over shares held by a revocable trust and Tellus BioVentures LLC. He disclaims beneficial ownership of these securities except to the extent of his pecuniary interest, limiting how his ownership is treated legally.

What does the weighted average price disclosure mean for the ZBIO CEO’s stock purchase?

The weighted average price of $16.88 reflects multiple trades executed between $16.59 and $16.97. The filing notes the CEO will provide detailed trade-by-trade pricing information to the issuer, security holders, or SEC staff upon request for additional transparency.