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  4. [Form 4] Aktis Oncology, Inc. Insider Trading Activity

Aktis Oncology (AKTS) funds convert preferred stock and buy shares

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

Rhea-AI Filing Summary

Aktis Oncology large shareholders affiliated with MPM BioVentures 2018 reported major equity changes tied to the company’s initial public offering. On January 12, 2026, entities in the group converted Series Seed, Series A and Series B Redeemable Convertible Preferred Stock into common shares at a 3.8044-for-1 ratio, resulting in 1,314,262, 5,914,197 and 1,577,119 shares of common stock from each series, respectively. The group also reported purchasing an additional 1,112,777 common shares at $18 per share. Following these transactions, the reporting entities indirectly held a total of 10,260,064 Aktis Oncology common shares spread across several investment funds. The reporting persons state that they disclaim beneficial ownership except to the extent of their pecuniary interest.

Positive

  • None.

Negative

  • None.
Insider MPM BIOVENTURES 2018, L.P., EVNIN LUKE, MPM BIOVENTURES 2018 (B), L.P., MPM BioVentures 2018 LLC, MPM BioVentures 2018 GP LLC, MPM ASSET MANAGEMENT INVESTORS BV2018 LLC, MPM ONCOLOGY INNOVATIONS FUND LP, MPM Oncology Innovations Fund GP LLC
Role 10% Owner | 10% Owner | 10% Owner | 10% Owner | 10% Owner | 10% Owner | 10% Owner | 10% Owner
Bought 1,112,777 shs ($20.03M)
Type Security Shares Price Value
Conversion Series Seed Redeemable Convertible Preferred Stock 5,000,000 $0.00 --
Conversion Series A Redeemable Convertible Preferred Stock 22,500,000 $0.00 --
Conversion Series B Redeemable Convertible Preferred Stock 6,000,000 $0.00 --
Conversion Common Stock 1,314,262 $0.00 --
Conversion Common Stock 5,914,197 $0.00 --
Conversion Common Stock 1,577,119 $0.00 --
Purchase Common Stock 1,112,777 $18.00 $20.03M
Holdings After Transaction: Series Seed Redeemable Convertible Preferred Stock — 0 shares (Indirect, See Footnote); Series A Redeemable Convertible Preferred Stock — 0 shares (Indirect, See Footnote); Series B Redeemable Convertible Preferred Stock — 0 shares (Indirect, See Footnote); Common Stock — 1,655,971 shares (Indirect, See Footnote)
Footnotes (1)
  1. The shares of common stock were issued upon conversion as follows: 556,810 by MPM BioVentures 2018, L.P. ("BV 2018"), 29,593 by MPM BioVentures 2018 (B), L.P. ("BV 2018(B)"), 10,988 by MPM Asset Management Investors BV2018 LLC ("AM BV2018"), 119,478 by MPM Oncology Innovations Fund, L.P. ("MPM Oncology") and 597,393 by Oncology Impact Private Investment Fund 2, L.P. ("MPM Oncology Impact"). MPM BioVentures 2018 GP LLC and MPM BioVentures 2018 LLC ("BV2018 LLC") are the direct and indirect general partners of BV 2018 and BV 2018(B). BV 2018 LLC is the manager of AM BV2018. Drs. Evnin and Gadicke are managing directors of BV 2018 LLC and managers of MPM Oncology Innovations Fund GP LLC, which is the general partner of MPM Oncology. Dr. Gadicke is the managing member of MPM Oncology Investments 2 LLC, which is the general partner of MPM Oncology Impact. Each share of Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock automatically converted into shares of the Issuer's Common Stock on a 3.8044-for-1 basis into the number of shares of Common Stock shown in Column 7 without payment of further consideration upon the closing of the initial public offering of the Issuer's Common Stock. The Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock had no expiration date. The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein. The shares are held as follows: 341,709 by MPM Asset Management LLC ("MPM AM"), 556,810 by BV 2018, 29,593 by BV 2018(B), 10,988 by AM BV2018, 119,478 by MPM Oncology and 597,393 by MPM Oncology Impact. Dr. Gadicke is the manager of MPM AM. The shares of common stock were issued upon conversion as follows: 2,505,648 by BV 2018, 133,170 by BV 2018(B), 49,452 by AM BV2018, 537,654 by MPM Oncology and 2,688,273 by MPM Oncology Impact. The shares are held as follows: 341,709 by MPM AM, 3,062,458 by BV 2018, 162,763 by BV 2018(B), 60,440 by AM BV2018, 657,132 by MPM Oncology and 3,285,666 by MPM Oncology Impact. The shares of common stock were issued upon conversion as follows: 668,173 by BV 2018, 35,512 by BV 2018(B), 13,187 by AM BV2018, 143,374 by MPM Oncology and 716,873 by MPM Oncology Impact. The shares are held as follows: 341,709 by MPM AM, 3,730,631 by BV 2018, 198,275 by BV 2018(B), 73,627 by AM BV2018, 800,506 by MPM Oncology and 4,002,539 by MPM Oncology Impact. The shares were purchased as follows: 219,897 by BV 2018, 8,689 by BV 2018(B), 4,284 by AM BV2018, 46,574 by MPM Oncology and 833,333 by MPM Oncology Impact. The shares are held as follows: 341,709 by MPM AM, 3,950,528 by BV 2018, 206,964 by BV 2018(B), 77,911 by AM BV2018, 847,080 by MPM Oncology and 4,835,872 by MPM Oncology Impact.
Form 4 Insider Transactions: What Each Field Means →
SEC Form 4
FORM 4 UNITED 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*
MPM BIOVENTURES 2018, L.P.
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
Aktis Oncology, Inc. [ AKTS ] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director X 10% Owner
Officer (give title below) Other (specify below)
3. Date of Earliest Transaction (Month/Day/Year)
01/12/2026
4. If Amendment, Date of Original Filed (Month/Day/Year)
 6. Individual or Joint/Group Filing (Check Applicable Line)
Form filed by One Reporting Person
X Form filed by More than One Reporting Person
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)
Code V Amount (A) or (D) Price
Common Stock 01/12/2026 C 1,314,262(1) A (2) 1,655,971 I See Footnote(3)(4)
Common Stock 01/12/2026 C 5,914,197(5) A (2) 7,570,168 I See Footnote(3)(6)
Common Stock 01/12/2026 C 1,577,119(7) A (2) 9,147,287 I See Footnote(3)(8)
Common Stock 01/12/2026 P 1,112,777(9) A $18 10,260,064 I See Footnote(3)(10)
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)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Series Seed Redeemable Convertible Preferred Stock (2) 01/12/2026 C 5,000,000 (2) (2) Common Stock 1,314,262 $0(2) 0 I See Footnote(1)(3)
Series A Redeemable Convertible Preferred Stock (2) 01/12/2026 C 22,500,000 (2) (2) Common Stock 5,914,197 $0(2) 0 I See Footnote(3)(5)
Series B Redeemable Convertible Preferred Stock (2) 01/12/2026 C 6,000,000 (2) (2) Common Stock 1,577,119 $0(2) 0 I See Footnote(3)(7)
1. Name and Address of Reporting Person*
MPM BIOVENTURES 2018, L.P.
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
EVNIN LUKE
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
MPM BIOVENTURES 2018 (B), L.P.
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
MPM BioVentures 2018 LLC
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
MPM BioVentures 2018 GP LLC
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
MPM ASSET MANAGEMENT INVESTORS BV2018 LLC
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
MPM ONCOLOGY INNOVATIONS FUND LP
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
1. Name and Address of Reporting Person*
MPM Oncology Innovations Fund GP LLC
(Last) (First) (Middle)
C/O MPM BIOIMPACT LLC
399 BOYLSTON STREET, SUITE 1100
(Street)
BOSTON MA 02116
(City) (State) (Zip)
Relationship of Reporting Person(s) to Issuer
Director X 10% Owner
Officer (give title below) Other (specify below)
Explanation of Responses:
1. The shares of common stock were issued upon conversion as follows: 556,810 by MPM BioVentures 2018, L.P. ("BV 2018"), 29,593 by MPM BioVentures 2018 (B), L.P. ("BV 2018(B)"), 10,988 by MPM Asset Management Investors BV2018 LLC ("AM BV2018"), 119,478 by MPM Oncology Innovations Fund, L.P. ("MPM Oncology") and 597,393 by Oncology Impact Private Investment Fund 2, L.P. ("MPM Oncology Impact"). MPM BioVentures 2018 GP LLC and MPM BioVentures 2018 LLC ("BV2018 LLC") are the direct and indirect general partners of BV 2018 and BV 2018(B). BV 2018 LLC is the manager of AM BV2018. Drs. Evnin and Gadicke are managing directors of BV 2018 LLC and managers of MPM Oncology Innovations Fund GP LLC, which is the general partner of MPM Oncology. Dr. Gadicke is the managing member of MPM Oncology Investments 2 LLC, which is the general partner of MPM Oncology Impact.
2. Each share of Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock automatically converted into shares of the Issuer's Common Stock on a 3.8044-for-1 basis into the number of shares of Common Stock shown in Column 7 without payment of further consideration upon the closing of the initial public offering of the Issuer's Common Stock. The Series Seed Redeemable Convertible Preferred Stock, Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock had no expiration date.
3. The Reporting Persons disclaim beneficial ownership of the securities except to the extent of his or its pecuniary interest therein.
4. The shares are held as follows: 341,709 by MPM Asset Management LLC ("MPM AM"), 556,810 by BV 2018, 29,593 by BV 2018(B), 10,988 by AM BV2018, 119,478 by MPM Oncology and 597,393 by MPM Oncology Impact. Dr. Gadicke is the manager of MPM AM.
5. The shares of common stock were issued upon conversion as follows: 2,505,648 by BV 2018, 133,170 by BV 2018(B), 49,452 by AM BV2018, 537,654 by MPM Oncology and 2,688,273 by MPM Oncology Impact.
6. The shares are held as follows: 341,709 by MPM AM, 3,062,458 by BV 2018, 162,763 by BV 2018(B), 60,440 by AM BV2018, 657,132 by MPM Oncology and 3,285,666 by MPM Oncology Impact.
7. The shares of common stock were issued upon conversion as follows: 668,173 by BV 2018, 35,512 by BV 2018(B), 13,187 by AM BV2018, 143,374 by MPM Oncology and 716,873 by MPM Oncology Impact.
8. The shares are held as follows: 341,709 by MPM AM, 3,730,631 by BV 2018, 198,275 by BV 2018(B), 73,627 by AM BV2018, 800,506 by MPM Oncology and 4,002,539 by MPM Oncology Impact.
9. The shares were purchased as follows: 219,897 by BV 2018, 8,689 by BV 2018(B), 4,284 by AM BV2018, 46,574 by MPM Oncology and 833,333 by MPM Oncology Impact.
10. The shares are held as follows: 341,709 by MPM AM, 3,950,528 by BV 2018, 206,964 by BV 2018(B), 77,911 by AM BV2018, 847,080 by MPM Oncology and 4,835,872 by MPM Oncology Impact.
Remarks:
This filing is 1 of 2 identical filings due to limitations on number of Reporting Persons. See Form 4 filed by Ansbert Gadicke.
/s/ Luke Evnin 01/14/2026
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2018 LLC, the managing member of MPM BioVentures 2018 GP LLC, the GP of MPM BioVentures 2018 (B), L 01/14/2026
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2018 LLC 01/14/2026
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2018 LLC, the managing member of MPM BioVentures 2018 GP LLC 01/14/2026
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2018 LLC, the managing member of MPM BioVentures 2018 GP LLC, the GP of MPM BioVentures 2018, L.P. 01/14/2026
/s/ Ansbert Gadicke, managing director of MPM BioVentures 2018 LLC, the manager of MPM Asset Management Investors BV2018 LLC 01/14/2026
/s/ Ansbert Gadicke, manager of MPM Oncology Innovations Fund GP LLC 01/14/2026
/s/ Ansbert Gadicke, manager of MPM Oncology Innovations Fund GP LLC, the general partner of MPM Oncology Innovations Fund, L.P. 01/14/2026
** Signature of Reporting Person Date
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.

Source: View Original Filing on SEC EDGAR

FAQ

What insider activity did Aktis Oncology (AKTS) report in this Form 4?

The filing shows that investment entities affiliated with MPM BioVentures 2018 and related funds converted preferred stock into Aktis Oncology common shares and also purchased additional common stock in connection with the company’s initial public offering.

How much preferred stock was converted into Aktis Oncology (AKTS) common shares?

The filing reports the conversion of 5,000,000 shares of Series Seed Redeemable Convertible Preferred Stock, 22,500,000 shares of Series A Redeemable Convertible Preferred Stock and 6,000,000 shares of Series B Redeemable Convertible Preferred Stock into common stock at a 3.8044-for-1 ratio.

How many Aktis Oncology (AKTS) common shares were issued from each preferred series?

Upon conversion, the preferred shares resulted in 1,314,262 common shares from the Series Seed, 5,914,197 from the Series A and 1,577,119 from the Series B Redeemable Convertible Preferred Stock.

Did the reporting entities buy additional Aktis Oncology (AKTS) shares for cash?

Yes. The filing shows a purchase of 1,112,777 Aktis Oncology common shares at a price of $18 per share, reported as indirectly owned through the investment entities.

What is the total Aktis Oncology (AKTS) common stock position after these transactions?

After the conversions and the share purchase, the reporting entities together indirectly held 10,260,064 shares of Aktis Oncology common stock, allocated among multiple MPM-affiliated funds and entities.

Do the reporting persons claim full beneficial ownership of the reported Aktis Oncology (AKTS) shares?

No. According to the footnotes, the reporting persons disclaim beneficial ownership of the securities except to the extent of their pecuniary interest in the various investment entities that hold the shares.