PepGen Inc. ownership disclosure: Commodore Capital LP and related filers report beneficial ownership of 3,544,101 shares of common stock, representing 5.1% of the class. The filing is a Schedule 13G reporting holdings as of 03/04/2026, based on 69,115,292 shares outstanding as of February 26, 2026.
The report states the Firm is investment manager to Commodore Capital Master LP and that Michael Kramarz and Robert Egen Atkinson exercise investment discretion for the aggregated position.
Positive
None.
Negative
None.
Insights
Passive 13G filing shows a >5% stake disclosed by Commodore Capital.
Commodore Capital LP and affiliated filers disclosed beneficial ownership of 3,544,101 shares or 5.1% as of 03/04/2026. The filing is on Schedule 13G, which typically indicates a passive investment intent rather than an activist approach.
Control and voting are reported as shared; subsequent filings could show changes if the firm adopts an active strategy or exceeds disclosure thresholds requiring different SEC treatment.
Position size is material relative to outstanding shares but below common takeover thresholds.
The disclosed position equals 3,544,101 shares against 69,115,292 shares outstanding (as of 02/26/2026), giving a 5.1% stake. Reported powers are shared voting and shared dispositive power.
Cash‑flow treatment and any trading intent are not stated in the excerpt; future filings would disclose any active changes to holdings or voting intentions.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
PepGen Inc.
(Name of Issuer)
Common stock, par value $0.0001 per share
(Title of Class of Securities)
03/04/2026
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)
SCHEDULE 13G
CUSIP Number(s):
1
Names of Reporting Persons
Commodore Capital LP
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
3,544,101.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
3,544,101.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
3,544,101.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
5.1 %
12
Type of Reporting Person (See Instructions)
IA, PN
SCHEDULE 13G
CUSIP Number(s):
1
Names of Reporting Persons
Commodore Capital Master LP
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
CAYMAN ISLANDS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
3,544,101.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
3,544,101.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
3,544,101.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
5.1 %
12
Type of Reporting Person (See Instructions)
PN
SCHEDULE 13G
CUSIP Number(s):
1
Names of Reporting Persons
Robert Egen Atkinson
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
3,544,101.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
3,544,101.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
3,544,101.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
5.1 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
CUSIP Number(s):
1
Names of Reporting Persons
Michael Kramarz
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
3,544,101.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
3,544,101.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
3,544,101.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
5.1 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
PepGen Inc.
(b)
Address of issuer's principal executive offices:
321 Harrison Avenue, 8th Floor, Boston, MASSACHUSETTS, 02118.
Item 2.
(a)
Name of person filing:
Commodore Capital LP
Commodore Capital Master LP
Robert Egen Atkinson
Michael Kramarz
Each a "Filer."
(b)
Address or principal business office or, if none, residence:
The address for Commodore Capital LP, Robert Egen Atkinson, and Michael Kramarz is 444 Madison Avenue, Floor 35, New York, NY 10022.
The address for Commodore Capital Master LP is c/o Maples Corporate Services Limited, Ugland House, South Church Street, PO Box 309, Grand Cayman KY1-1104, Cayman Islands.
(c)
Citizenship:
See Item 4 of the cover page for each Filer.
(d)
Title of class of securities:
Common stock, par value $0.0001 per share
(e)
CUSIP No.:
713317105
Item 3.
If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
(k)
Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.
Ownership
(a)
Amount beneficially owned:
See Item 9 of the cover page for each Filer.
This report on Schedule 13G is being filed by Commodore Capital LP (the "Firm"), Commodore Capital Master LP ("Commodore Master"), Michael Kramarz, and Robert Egen Atkinson. The Firm is the investment manager to Commodore Master. As of March 4, 2026, the Firm may be deemed to beneficially own an aggregate of 3,544,101 shares of Common stock, par value $0.0001 per share (the "Common Stock"), of PepGen Inc. (the "Issuer"). The Firm, as the investment manager to Commodore Master, may be deemed to beneficially own these securities. Michael Kramarz and Robert Egen Atkinson are the managing partners of the Firm and exercise investment discretion with respect to these securities. Ownership percentages are based on 69,115,292 Common Stock reported as issued and outstanding as of February 26, 2026 in the Issuer's Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 4, 2026.
(b)
Percent of class:
See Item 11 of the cover page for each Filer.
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
See Item 5 of the cover page for each Filer.
(ii) Shared power to vote or to direct the vote:
See Item 6 of the cover page for each Filer.
(iii) Sole power to dispose or to direct the disposition of:
See Item 7 of the cover page for each Filer.
(iv) Shared power to dispose or to direct the disposition of:
See Item 8 of the cover page for each Filer.
Item 5.
Ownership of 5 Percent or Less of a Class.
Not Applicable
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
Not Applicable
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
Not Applicable
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
What stake did Commodore Capital report in PepGen (PEPG)?
They reported beneficial ownership of 3,544,101 shares, equal to 5.1% of PepGen's common stock. This percentage is based on 69,115,292 shares outstanding reported as of 02/26/2026 in the company's Form 10-K.
What filing did Commodore Capital use to disclose its PepGen holding?
Commodore Capital filed a Schedule 13G, indicating a passive reporting category for the position. The Schedule 13G in the excerpt lists ownership as of 03/04/2026 and names related filers and addresses.
Who within Commodore exercises investment discretion over the PepGen shares?
The filing names Michael Kramarz and Robert Egen Atkinson as managing partners who exercise investment discretion. The Firm is identified as investment manager to Commodore Capital Master LP in the disclosure.
Are the voting and dispositive powers sole or shared for this PepGen stake?
The report shows shared voting power and shared dispositive power for 3,544,101 shares. Sole voting and dispositive powers are reported as 0.00 for the filers in the excerpt.
What outstanding share count was used to calculate the 5.1% figure for PEPG?
The 5.1% ownership percentage is calculated using 69,115,292 shares outstanding as reported in PepGen's Form 10-K dated 02/26/2026, per the filing's stated reference.
