RA Capital discloses 9.1% Aclaris Therapeutics (ACRS) stake via 12.7M shares

Rhea-AI Filing Summary

RA Capital Management and affiliates reported a significant ownership position in Aclaris Therapeutics, Inc. RA Capital Healthcare Fund, L.P. directly holds 12,723,026 shares of Aclaris common stock. Based on 139,824,273 shares outstanding as of June 30, 2026, this represents 9.1% of the company’s common stock. RA Capital Management, L.P. serves as investment adviser to the Fund and has been delegated sole voting and dispositive power over these shares, while the Fund, RA Capital, Peter Kolchinsky, and Rajeev Shah each disclaim beneficial ownership except for purposes of Section 13(d) reporting.

Key Figures

Shares beneficially owned: 12,723,026 shares Percent of class: 9.1% Shares outstanding: 139,824,273 shares +1 more

4 metrics

Shares beneficially owned 12,723,026 shares Common stock of Aclaris Therapeutics held by RA Capital Healthcare Fund as of June 30, 2026

Percent of class 9.1% Portion of Aclaris common stock beneficially owned by each reporting person as of June 30, 2026

Shares outstanding 139,824,273 shares Aclaris common stock outstanding as of June 30, 2026, per Form 10-Q

Notice period on delegation 61 days Minimum notice required for the Fund to revoke delegation of voting and investment power to RA Capital

Key Terms

beneficial owner, Section 13(d) of the Act, Schedule 13G, dispositive power, +1 more

5 terms

beneficial owner regulatory

"may be deemed a beneficial owner, for purposes of Section 13(d) of the Act"

A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.

Section 13(d) of the Act regulatory

"for purposes of Section 13(d) of the Act, of any securities of the Issuer"

Schedule 13G regulatory

"The Reporting Persons expressly disclaim status as a "group" for purposes of this /A."

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

dispositive power financial

"sole power to dispose and the sole power to dispose of all securities held"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

voting power financial

"sole power to vote and the sole power to dispose of all securities"

Voting power is the ability shareholders have to influence a company's major decisions—like electing the board, approving mergers, or changing corporate rules—based on the voting rights attached to the shares they hold. For investors it matters because greater voting power is like holding more keys to a building: it gives you a stronger say over management choices and the company’s strategy, which can affect future value and risk.

FAQ

How many Aclaris Therapeutics (ACRS) shares does RA Capital Healthcare Fund hold?

RA Capital Healthcare Fund, L.P. directly holds 12,723,026 shares of Aclaris Therapeutics common stock. This position is reported as of June 30, 2026 in the Schedule 13G/A ownership filing.

What percentage of Aclaris Therapeutics (ACRS) does RA Capital beneficially own?

The reporting persons disclose beneficial ownership of 9.1% of Aclaris Therapeutics common stock. This percentage is based on 139,824,273 shares outstanding as of June 30, 2026, as reported in Aclaris’s Form 10-Q.

Who are the reporting persons on the Aclaris Therapeutics (ACRS) Schedule 13G/A?

The reporting persons are RA Capital Management, L.P., RA Capital Healthcare Fund, L.P., Peter Kolchinsky, and Rajeev Shah. They file jointly while expressly disclaiming status as a group for this Schedule 13G/A amendment.

Who has voting and dispositive power over RA Capital’s Aclaris (ACRS) shares?

RA Capital Management, L.P. has been delegated sole power to vote and dispose of all Aclaris shares held by the Fund. The Fund has divested voting and investment power and cannot revoke this delegation on less than 61 days’ notice.

Why do RA Capital and its principals disclaim beneficial ownership of Aclaris (ACRS) shares?

RA Capital, the Fund, Peter Kolchinsky, and Rajeev Shah disclaim beneficial ownership of the reported securities except for determining obligations under Section 13(d). They state the filing should not be deemed an admission of beneficial ownership for other purposes.

What is the reference share count used in RA Capital’s Aclaris (ACRS) ownership percentage?

The 9.1% ownership figure is calculated using 139,824,273 shares of Aclaris common stock outstanding. This share count comes from Aclaris’s Form 10-Q for the period including June 30, 2026, filed with the SEC on August 6, 2026.

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

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Available on EDGAR 08/14/2026 - 04:40 PM Accepted by SEC EDGAR 08/14/2026 - 04:36 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

ACLARIS THERAPEUTICS, INC.

(Name of Issuer)

Common Stock, $0.00001 par value per share

(Title of Class of Securities)

00461U105

(CUSIP Number)

06/30/2026

(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)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 00461U105

1

Names of Reporting Persons

RA Capital Management, L.P.

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 12,723,026.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 12,723,026.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

12,723,026.00

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)

9.1 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP Number(s): 00461U105

1

Names of Reporting Persons

Peter Kolchinsky

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 12,723,026.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 12,723,026.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

12,723,026.00

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)

9.1 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

CUSIP Number(s): 00461U105

1

Names of Reporting Persons

Rajeev Shah

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 12,723,026.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 12,723,026.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

12,723,026.00

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)

9.1 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

CUSIP Number(s): 00461U105

1

Names of Reporting Persons

RA Capital Healthcare Fund, L.P.

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 12,723,026.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 12,723,026.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

12,723,026.00

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)

9.1 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: ACLARIS THERAPEUTICS, INC.
(b)	Address of issuer's principal executive offices: 701 LEE ROAD, SUITE 103, WAYNE, PA, 19087.
Item 2.
(a)	Name of person filing: The names of the persons filing this report (collectively, the "Reporting Persons") are: RA Capital Management, L.P. ("RA Capital") Peter Kolchinsky ("Dr. Kolchinsky") Rajeev Shah ("Mr. Shah") RA Capital Healthcare Fund, L.P. (the "Fund") The Reporting Persons expressly disclaim status as a "group" for purposes of this Schedule 13G/A.
(b)	Address or principal business office or, if none, residence: The address of the principal business office of each of the Reporting Persons is: c/o RA Capital Management, L.P., 200 Berkeley Street, 18th Floor, Boston MA 02116
(c)	Citizenship: RA Capital and the Fund are Delaware limited partnerships. Dr. Kolchinsky and Mr. Shah are United States citizens.
(d)	Title of class of securities: Common Stock, $0.00001 par value per share
(e)	CUSIP No.: 00461U105
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: Row 9 of each Reporting Person's cover page to this Schedule 13G/A sets forth the aggregate number of shares of common stock of the Issuer beneficially owned by such Reporting Person as of June 30, 2026 and is incorporated by reference. The Fund directly holds 12,723,026 shares of the Issuer's common stock. RA Capital Healthcare Fund GP, LLC is the general partner of the Fund. The general partner of RA Capital is RA Capital Management GP, LLC, of which Dr. Kolchinsky and Mr. Shah are the controlling persons. RA Capital serves as investment adviser for the Fund and may be deemed a beneficial owner, for purposes of Section 13(d) of the Act, of any securities of the Issuer held by the Fund. The Fund has delegated to RA Capital the sole power to vote and the sole power to dispose of all securities held in the Fund's portfolio, including the shares of the Issuer's common stock reported herein. Because the Fund has divested voting and investment power over the reported securities it holds and may not revoke that delegation on less than 61 days' notice, the Fund disclaims beneficial ownership of the securities it holds for purposes of Section 13(d) of the Act. As managers of RA Capital, Dr. Kolchinsky and Mr. Shah may be deemed beneficial owners, for purposes of Section 13(d) of the Act, of any securities of the Issuer beneficially owned by RA Capital. RA Capital, Dr. Kolchinsky, and Mr. Shah disclaim beneficial ownership of the securities reported in this Schedule 13G/A other than for the purpose of determining their obligations under Section 13(d) of the Act, and the filing of this Schedule 13G shall not be deemed an admission that either RA Capital, Dr. Kolchinsky, or Mr. Shah is the beneficial owner of such securities for any other purpose.
(b)	Percent of class: Row 11 of each Reporting Person's cover page to this Schedule 13G/A sets forth the percentages of the shares of common stock of the Issuer beneficially owned by such Reporting Person as of June 30, 2026 and is incorporated by reference. The percentage set forth in each row 11 is based upon 139,824,273 shares of common stock outstanding as of June 30, 2026, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (the "SEC") on August 6, 2026.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: Row 5 of each Reporting Person's cover page to this Schedule 13G/A sets forth the sole power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2026 and is incorporated by reference.
	(ii) Shared power to vote or to direct the vote: Row 6 of each Reporting Person's cover page to this Schedule 13G/A sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2026 and is incorporated by reference.
	(iii) Sole power to dispose or to direct the disposition of: Row 7 of each Reporting Person's cover page to this Schedule 13G/A sets forth the sole power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2026 and is incorporated by reference.
	(iv) Shared power to dispose or to direct the disposition of: Row 8 of each Reporting Person's cover page to this Schedule 13G/A sets forth the shared power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2026 and is incorporated by reference.
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.

RA Capital Management, L.P.

Signature:	/s/ Peter Kolchinsky
Name/Title:	By Peter Kolchinsky, Authorized Signatory
Date:	08/14/2026

Peter Kolchinsky

Signature:	/s/ Peter Kolchinsky
Name/Title:	Peter Kolchinsky
Date:	08/14/2026

Rajeev Shah

Signature:	/s/ Rajeev Shah
Name/Title:	Rajeev Shah
Date:	08/14/2026

RA Capital Healthcare Fund, L.P.

Signature:	/s/ Peter Kolchinsky
Name/Title:	By RA Capital Healthcare Fund GP, LLC, its General Partner, By Peter Kolchinsky, Manager
Date:	08/14/2026

Exhibit Information

Exhibit 99.1 Joint Filing Agreement (incorporated by reference to Exhibit 99.1 to Schedule 13G filed on April 7, 2026)