BVF discloses 19.7% stake in MoonLake

Rhea-AI Filing Summary

MoonLake Immunotherapeutics’ major shareholder group BVF has updated its ownership disclosure in Amendment No. 6 to its Schedule 13D. The amendment reflects that BVF-affiliated funds and accounts beneficially own 16,001,284 Class A ordinary shares, representing about 19.7% of MoonLake’s 81,134,066 shares outstanding as of June 25, 2026, following a recent offering.

The filing also notes director Spike Loy’s beneficial ownership of 25,667 shares through options exercisable within sixty days. On June 17, 2026, he was granted stock options to purchase 22,195 shares at an exercise price of $19.19 per share, vesting by June 17, 2027 or the next annual meeting and expiring on June 17, 2036.

Key Figures

Shares outstanding: 81,134,066 shares BVF group aggregate holding: 16,001,284 shares BVF stake: 8,302,735 shares +4 more

7 metrics

Shares outstanding 81,134,066 shares Class A ordinary shares outstanding as of June 25, 2026

BVF group aggregate holding 16,001,284 shares Beneficially owned by BVF, BVF2, Trading Fund OS and Partners Managed Account; 19.7% of outstanding

BVF stake 8,302,735 shares Beneficial ownership by BVF, about 10.2% of shares outstanding

BVF2 stake 6,599,722 shares Beneficial ownership by BVF2, about 8.1% of shares outstanding

Trading Fund OS stake 1,039,238 shares Beneficial ownership by Biotechnology Value Trading Fund OS, about 1.3% of shares outstanding

Spike Loy beneficial ownership 25,667 shares Shares issuable upon exercise of options exercisable within sixty days; about 0.03% of class

Spike Loy option grant 22,195 options at $19.19/share Granted June 17, 2026; vest by June 17, 2027 or next annual meeting; expire June 17, 2036

Key Terms

beneficially own, Schedule 13D, Prospectus Supplement, stock options, +1 more

5 terms

beneficially own financial

"The aggregate percentage of Shares reported owned by each person named herein is based on 81,134,066 Shares outstanding..."

Beneficially own means having the economic rights and risks of a security—such as the right to receive dividends, sell the shares, or profit from price changes—whether or not your name appears on the official share register. Think of it like renting a car: you use it and reap the benefits even if the title lists someone else. Investors care because beneficial ownership determines who truly controls value, must be disclosed under securities rules, and can signal potential influence or trading activity that affects a stock’s price.

Schedule 13D regulatory

"This Amendment No. 6 to the is being filed due to a change in the percentage..."

A Schedule 13D is a legal document that investors file with regulators when they buy a large enough stake in a company to potentially influence its management or decisions. It provides details about the investor’s intention, ownership stake, and plans, helping other investors understand who is gaining control and what their motives might be.

Prospectus Supplement regulatory

"following the closing of the Issuer's offering as reported in the Issuer's Prospectus Supplement filed..."

A prospectus supplement is an additional document provided alongside a company's main offering details, offering updated or extra information about a specific financial product being sold. It helps investors understand the latest terms, risks, and details of the investment, similar to how an update or revision clarifies or expands on original instructions, ensuring they have current and complete information before making a decision.

stock options financial

"On June 17, 2026, Mr. Loy was granted stock options in connection with his service as a director..."

Stock options are agreements that give a person the right to buy or sell a company's stock at a specific price within a certain time frame. They are often used as a reward or incentive, similar to a coupon that can be used later if the stock price rises, allowing the holder to make a profit.

exercise price financial

"have an exercise price of $19.19 per Share and (c) expire on June 17, 2036."

The exercise price is the fixed amount at which you can buy or sell an asset, like a stock, when using an options contract. It matters because it helps determine whether exercising the option will be profitable or not, depending on the current market price. Think of it as the set price you agree on today to buy or sell later.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What does BVF’s Amendment No. 6 to its Schedule 13D for MLTX report?

The amendment reports updated ownership after MoonLake’s recent share offering. BVF-affiliated entities now beneficially own 16,001,284 Class A ordinary shares, reflecting their stake based on 81,134,066 shares outstanding as of June 25, 2026.

How many MoonLake (MLTX) shares does the BVF group beneficially own and what percentage is this?

BVF-related funds and accounts beneficially own 16,001,284 Class A ordinary shares. This represents approximately 19.7% of MoonLake’s 81,134,066 shares outstanding as of June 25, 2026, following the offering described in the issuer’s Prospectus Supplement.

What are the individual MoonLake (MLTX) stakes of BVF, BVF2 and Trading Fund OS?

BVF beneficially owns 8,302,735 shares, about 10.2% of shares outstanding. BVF2 holds 6,599,722 shares, about 8.1%, while Biotechnology Value Trading Fund OS owns 1,039,238 shares, about 1.3%, all calculated against 81,134,066 outstanding shares.

What change triggered BVF’s Schedule 13D/A Amendment No. 6 for MoonLake (MLTX)?

The amendment was triggered by a change in BVF’s ownership percentage caused by an increase in MoonLake’s shares outstanding. The new percentages are based on 81,134,066 shares outstanding after the issuer’s offering described in a June 24, 2026 Prospectus Supplement.

What MoonLake (MLTX) stock options were granted to director Spike Loy?

On June 17, 2026, Spike Loy received options to purchase 22,195 MoonLake shares. These options vest in full by June 17, 2027 or the next annual shareholders’ meeting, have a $19.19 exercise price per share, and expire on June 17, 2036.

Has the BVF group traded MoonLake (MLTX) shares recently according to this amendment?

The amendment states that, other than arrangements described in Item 6, none of the reporting persons entered into transactions in MoonLake securities during the past 60 days. The notable new item is the June 17, 2026 stock option grant to director Spike Loy.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 06/29/2026 - 05:20 PM EDT Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 6)

MoonLake Immunotherapeutics

(Name of Issuer)

Class A ordinary share, par value $0.0001 per share

(Title of Class of Securities)

61559X104

(CUSIP Number)

JAMES KRATKY
BVF PARTNERS L.P., 44 Montgomery St., 40th Floor
San Francisco, CA, 94104
415-525-8830

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

06/25/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

schemaVersion:

SCHEDULE 13D

CUSIP Number(s): 61559X104

1

Name of reporting person

BIOTECHNOLOGY VALUE FUND L P

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 8,302,735.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 8,302,735.00

11

Aggregate amount beneficially owned by each reporting person

8,302,735.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

10.2 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP Number(s): 61559X104

1

Name of reporting person

BVF I GP LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 8,302,735.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 8,302,735.00

11

Aggregate amount beneficially owned by each reporting person

8,302,735.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

10.2 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP Number(s): 61559X104

1

Name of reporting person

BIOTECHNOLOGY VALUE FUND II LP

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 6,599,722.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 6,599,722.00

11

Aggregate amount beneficially owned by each reporting person

6,599,722.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

8.1 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP Number(s): 61559X104

1

Name of reporting person

BVF II GP LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 6,599,722.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 6,599,722.00

11

Aggregate amount beneficially owned by each reporting person

6,599,722.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

8.1 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP Number(s): 61559X104

1

Name of reporting person

Biotechnology Value Trading Fund OS LP

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 1,039,238.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 1,039,238.00

11

Aggregate amount beneficially owned by each reporting person

1,039,238.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.3 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP Number(s): 61559X104

1

Name of reporting person

BVF Partners OS Ltd.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 1,039,238.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 1,039,238.00

11

Aggregate amount beneficially owned by each reporting person

1,039,238.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

1.3 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

CUSIP Number(s): 61559X104

1

Name of reporting person

BVF GP HOLDINGS LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 14,902,457.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 14,902,457.00

11

Aggregate amount beneficially owned by each reporting person

14,902,457.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

18.4 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP Number(s): 61559X104

1

Name of reporting person

BVF PARTNERS L P/IL

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 16,001,284.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 16,001,284.00

11

Aggregate amount beneficially owned by each reporting person

16,001,284.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

19.7 %

14

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13D

CUSIP Number(s): 61559X104

1

Name of reporting person

BVF INC/IL

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 16,001,284.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 16,001,284.00

11

Aggregate amount beneficially owned by each reporting person

16,001,284.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

19.7 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

CUSIP Number(s): 61559X104

1

Name of reporting person

LAMPERT MARK N

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 16,001,284.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 16,001,284.00

11

Aggregate amount beneficially owned by each reporting person

16,001,284.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

19.7 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

CUSIP Number(s): 61559X104

1

Name of reporting person

Loy Spike

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 25,667.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 25,667.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

25,667.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.03 %

14

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Class A ordinary share, par value $0.0001 per share
(b)	Name of Issuer: MoonLake Immunotherapeutics
(c)	Address of Issuer's Principal Executive Offices: DORFSTRASSE 29, ZUG, SWITZERLAND , 6300.
Item 1 Comment: This Amendment No. 6 to the Schedule 13D is being filed due to a change in the percentage of the outstanding number of Shares owned by the Reporting Persons due to an increase in the number of Shares outstanding.
Item 5.	Interest in Securities of the Issuer
(a)	Item 5(a) is hereby amended and restated to read as follows: The aggregate percentage of Shares reported owned by each person named herein is based on 81,134,066 Shares outstanding as of June 25, 2026, which is the total number of Shares outstanding following the closing of the Issuer's offering as reported in the Issuer's Prospectus Supplement filed with the Securities and Exchange Commission on June 24, 2026. As of the date hereof, (i) BVF beneficially owned 8,302,735 Shares, representing percentage ownership of approximately 10.2% of the Shares outstanding, (ii) BVF2 beneficially owned 6,599,722 Shares, representing percentage ownership of approximately 8.1% of the Shares outstanding, (iii) Trading Fund OS beneficially owned 1,039,238 Shares, representing percentage ownership of approximately 1.3% of the Shares outstanding, and (iv) 59,589 Shares were held in the Partners Managed Account, representing percentage ownership of less than 1% of the Shares outstanding. BVF GP, as the general partner of BVF, may be deemed to beneficially own the 8,302,735 Shares beneficially owned by BVF, representing percentage ownership of approximately 10.2% of the Shares outstanding. BVF2 GP, as the general partner of BVF2, may be deemed to beneficially own the 6,599,722 Shares beneficially owned by BVF2, representing percentage ownership of approximately 8.1% of the Shares outstanding. Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 1,039,238 Shares beneficially owned by Trading Fund OS, representing percentage ownership of approximately 1.3% of the Shares outstanding. BVF GPH, as the sole member of each of BVF GP and BVF2 GP, may be deemed to beneficially own the 14,902,457 Shares beneficially owned in the aggregate by BVF and BVF2, representing percentage ownership of approximately 18.4% of the Shares outstanding. Partners, as the investment manager of BVF, BVF2, Trading Fund OS and the Partners Managed Account and the sole member of Partners OS, may be deemed to beneficially own the 16,001,284 Shares beneficially owned in the aggregate by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Account, representing percentage ownership of approximately 19.7% of the Shares outstanding. BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 16,001,284 Shares beneficially owned by Partners, representing percentage ownership of approximately 19.7% of the Shares outstanding. Mr. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the 16,001,284 Shares beneficially owned by BVF Inc., representing percentage ownership of approximately 19.7% of the Shares outstanding. As of the date hereof, Mr. Loy beneficially owned 25,667 Shares, which consist of Shares issuable upon the exercise of certain options that are exercisable within sixty days hereof, representing percentage ownership of less than 1%. The foregoing should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of any Shares owned by another Reporting Person. BVF GP disclaims beneficial ownership of the Shares beneficially owned by BVF. BVF2 GP disclaims beneficial ownership of the Shares beneficially owned by BVF2. Partners OS disclaims beneficial ownership of the Shares beneficially owned by Trading Fund OS. BVF GPH disclaims beneficial ownership of the Shares beneficially owned by BVF and BVF2. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the Shares beneficially owned by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Account. Mr. Loy disclaims beneficial ownership of the Shares reported herein that he does not directly own.
(c)	Item 5(c) is hereby amended and restated to read as follows: Other than as set forth in Item 6, none of the Reporting Persons have entered into any transactions in the securities of the Issuer during the past 60 days.
Item 6.	Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer
	Item 6 is hereby amended to add the following: On June 17, 2026, Mr. Loy was granted stock options in connection with his service as a director of the Issuer that represent a right to purchase 22,195 Shares. Such options (a) will vest in full on the earlier of (i) June 17, 2027 and (ii) the date of the Issuer's next annual general meeting of shareholders, subject to Mr. Loy's continued service to the Issuer, (b) have an exercise price of $19.19 per Share and (c) expire on June 17, 2036.

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.

BIOTECHNOLOGY VALUE FUND L P

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	06/29/2026

BVF I GP LLC

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	06/29/2026

BIOTECHNOLOGY VALUE FUND II LP

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	06/29/2026

BVF II GP LLC

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	06/29/2026

Biotechnology Value Trading Fund OS LP

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	06/29/2026

BVF Partners OS Ltd.

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	06/29/2026

BVF GP HOLDINGS LLC

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	06/29/2026

BVF PARTNERS L P/IL

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	06/29/2026

BVF INC/IL

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	06/29/2026

LAMPERT MARK N

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert
Date:	06/29/2026

Loy Spike

Signature:	/s/ Spike Loy
Name/Title:	Spike Loy
Date:	06/29/2026