Aktis Oncology (AKTS) funds convert preferred and buy stock in IPO filing

Rhea-AI Filing Summary

Aktis Oncology insider funds reported major share conversions and a purchase tied to its initial public offering. On January 12, 2026, investment entities linked to MPM converted 5,000,000 Series Seed, 22,500,000 Series A and 6,000,000 Series B Redeemable Convertible Preferred Stock into common shares at a 3.8044‑for‑1 rate, issuing 1,314,262, 5,914,197 and 1,577,119 common shares, respectively.

These common shares are held across multiple MPM vehicles, including MPM Asset Management LLC, several MPM BioVentures funds, MPM Oncology funds and Oncology Impact Private Investment Fund 2, L.P. The MPM‑affiliated funds also purchased 1,112,777 shares of Aktis Oncology common stock at $18 per share, bringing their indirectly held common stock to 10,260,064 shares. The reporting persons disclaim beneficial ownership of these securities except to the extent of their pecuniary interest.

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

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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^*

GADICKE ANSBERT

(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^*

GADICKE ANSBERT

(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 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^*

Oncology Impact Private Investment Fund 2, 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)

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 MPM BioVentures 2018, L.P.

	/s/ Ansbert Gadicke	01/14/2026
	/s/ Ansbert Gadicke, manager of MPM Asset Management LLC	01/14/2026
	/s/ Ansbert Gadicke, managing member of MPM Oncology Investments 2 LLC	01/14/2026
	/s/ Ansbert Gadicke, managing member of MPM Oncology Investments 2 LLC, the general partner of Oncology Impact Private Investment Fund 2, L.P.	01/14/2026
	** Signature of Reporting Person	Date
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FAQ

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

The filing shows MPM‑affiliated investment funds converting multiple series of redeemable convertible preferred stock into Aktis Oncology common shares and buying additional common stock, all reported as indirect ownership by the reporting persons.

How many preferred shares were converted into Aktis Oncology common stock?

The entities converted 5,000,000 Series Seed, 22,500,000 Series A and 6,000,000 Series B Redeemable Convertible Preferred Stock into common shares on January 12, 2026.

What conversion ratio was used for Aktis Oncology’s preferred stock?

Each share of Series Seed, Series A and Series B Redeemable Convertible Preferred Stock automatically converted into Aktis Oncology common stock on a 3.8044‑for‑1 basis upon the closing of the company’s initial public offering.

How many Aktis Oncology common shares did the MPM funds receive from conversion?

The preferred stock conversions issued 1,314,262, 5,914,197 and 1,577,119 Aktis Oncology common shares for the Series Seed, Series A and Series B preferred stock, respectively, allocated across several MPM‑related funds.

Did the MPM-affiliated entities buy additional Aktis Oncology shares for cash?

Yes. MPM BioVentures 2018, related MPM entities and Oncology funds purchased 1,112,777 Aktis Oncology common shares at $18 per share, as detailed in the footnotes.

What is the total Aktis Oncology common stock indirectly held after these transactions?

After the conversions and purchase, the filing reports that the MPM‑affiliated entities indirectly hold 10,260,064 shares of Aktis Oncology common stock, with the reporting persons disclaiming beneficial ownership beyond their pecuniary interest.

Who are the main entities associated with these Aktis Oncology insider holdings?

The holdings are spread among MPM Asset Management LLC, multiple MPM BioVentures funds, MPM Oncology Innovations Fund and Oncology Impact Private Investment Fund 2, L.P., with Dr. Ansbert Gadicke holding management roles in several of these entities.