0001346824-26-000119.txt : 20260427 0001346824-26-000119.hdr.sgml : 20260427 20260427164624 ACCESSION NUMBER: 0001346824-26-000119 CONFORMED SUBMISSION TYPE: SCHEDULE 13G PUBLIC DOCUMENT COUNT: 2 FILED AS OF DATE: 20260427 DATE AS OF CHANGE: 20260427 SUBJECT COMPANY: COMPANY DATA: COMPANY CONFORMED NAME: JATT II Acquisition Corp. CENTRAL INDEX KEY: 0002112446 STANDARD INDUSTRIAL CLASSIFICATION: BLANK CHECKS [6770] ORGANIZATION NAME: 05 Real Estate & Construction EIN: 000000000 STATE OF INCORPORATION: E9 FISCAL YEAR END: 1231 FILING VALUES: FORM TYPE: SCHEDULE 13G SEC ACT: 1934 Act SEC FILE NUMBER: 005-95633 FILM NUMBER: 26901711 BUSINESS ADDRESS: ADDRESS IS A NON US LOCATION: YES STREET 1: C/O APPLEBY GLOBAL SERVICES (CAYMAN) LTD STREET 2: 71 FORT STREET, PO BOX 500 CITY: GEORGE TOWN NON US STATE TERRITORY: GRAND CAYMAN PROVINCE COUNTRY: E9 ZIP: KY1-1106 BUSINESS PHONE: 201-688-0364 MAIL ADDRESS: ADDRESS IS A NON US LOCATION: YES STREET 1: C/O APPLEBY GLOBAL SERVICES (CAYMAN) LTD STREET 2: 71 FORT STREET, PO BOX 500 CITY: GEORGE TOWN NON US STATE TERRITORY: GRAND CAYMAN PROVINCE COUNTRY: E9 ZIP: KY1-1106 FILED BY: COMPANY DATA: COMPANY CONFORMED NAME: RA CAPITAL MANAGEMENT, L.P. CENTRAL INDEX KEY: 0001346824 ORGANIZATION NAME: EIN: 830406777 STATE OF INCORPORATION: DE FISCAL YEAR END: 1231 FILING VALUES: FORM TYPE: SCHEDULE 13G BUSINESS ADDRESS: STREET 1: 200 BERKELEY STREET, 18TH FLOOR CITY: BOSTON STATE: MA ZIP: 02116 BUSINESS PHONE: 617-778-2500 MAIL ADDRESS: STREET 1: 200 BERKELEY STREET, 18TH FLOOR CITY: BOSTON STATE: MA ZIP: 02116 FORMER COMPANY: FORMER CONFORMED NAME: RA CAPITAL MANAGEMENT, LLC DATE OF NAME CHANGE: 20051213 SCHEDULE 13G 1 primary_doc.xml X0202 SCHEDULE 13G 0001346824 XXXXXXXX LIVE Ordinary Shares, par value $0.0001 per share 04/20/2026 0002112446 JATT II Acquisition Corp G50765109 153 Central Avenue C/O 56 Westfield NJ 07091 Rule 13d-1(c) RA Capital Management, L.P. DE 0.00 500000.00 0.00 500000.00 500000.00 6.4 IA PN Peter Kolchinsky X1 0.00 500000.00 0.00 500000.00 500000.00 6.4 HC IN Rajeev Shah X1 0.00 500000.00 0.00 500000.00 500000.00 6.4 HC IN RA Capital Healthcare Fund, L.P. DE 0.00 500000.00 0.00 500000.00 500000.00 6.4 PN JATT II Acquisition Corp 153 Central Avenue, C/O 56, Westfield, NJ, 07091. 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. 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 RA Capital and the Fund are Delaware limited partnerships. Dr. Kolchinsky and Mr. Shah are United States citizens. Y Row 9 of each Reporting Person's cover page to this Schedule 13G sets forth the aggregate number of ordinary shares of the Issuer beneficially owned by such Reporting Person and is incorporated by reference. The Fund directly holds 500,000 ordinary shares. 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 ordinary shares of the Issuer 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 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. Row 11 of each Reporting Person's cover page to this Schedule 13G sets forth the percentages of ordinary shares of the Issuer beneficially owned by such Reporting Person and is incorporated by reference. Such percentage is based upon 7,800,000 ordinary shares outstanding as of April 20, 2026, as reported in the Issuer's final prospectus dated April 17, 2026 filed with the Securities and Exchange Commission (the "SEC") on April 17, 2026. Row 5 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference. Row 6 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference. Row 7 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference. Row 8 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference. Y Y Y Y Y N 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. Exhibit 99.1 Joint Filing Agreement RA Capital Management, L.P. /s/ Peter Kolchinsky By Peter Kolchinsky, Authorized Signatory 04/27/2026 Peter Kolchinsky /s/ Peter Kolchinsky Peter Kolchinsky 04/27/2026 Rajeev Shah /s/ Rajeev Shah Rajeev Shah 04/27/2026 RA Capital Healthcare Fund, L.P. /s/ Peter Kolchinsky By RA Capital Healthcare Fund GP, LLC, its General Partner, By Peter Kolchinsky, Manager 04/27/2026 EX-99.1 2 ex-99-04272026_080433.htm JOINT FILING AGREEMENT ex-99-04272026_080433.htm

EXHIBIT 99.1


JOINT FILING AGREEMENT


This Joint Filing Agreement, dated as of April 27, 2026, is by and among RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah and RA Capital Healthcare Fund, L.P. (the foregoing are collectively referred to herein as the “Filers”).


Each of the Filers may be required to file with the United States Securities and Exchange Commission a statement on Schedule 13G and/or 13D with respect to the ordinary shares, par value $0.0001 per share of JATT II Acquisition Corp beneficially owned by them from time to time.


Pursuant to and in accordance with Rule 13(d)(1)(k) promulgated under the Securities Exchange Act of 1934, as amended, the Filers hereby agree to file a single statement on Schedule 13G and/or 13D (and any amendments thereto) on behalf of each of such parties, and hereby further agree to file this Joint Filing Agreement as an exhibit to such statement, as required by such rule.


This Joint Filing Agreement may be terminated by any of the Filers upon one week’s prior written notice or such lesser period of notice as the Filers may mutually agree.


Executed and delivered as of the date first above written.



RA CAPITAL MANAGEMENT, L.P.


By:

/s/ Peter Kolchinsky

Name:

Peter Kolchinsky

Title:

Authorized Signatory



PETER KOLCHINSKY


/s/ Peter Kolchinsky



RAJEEV SHAH


/s/ Rajeev Shah



RA CAPITAL HEALTHCARE FUND, L.P.


By:

RA Capital Healthcare Fund GP, LLC

Its:

General Partner


By:

/s/ Peter Kolchinsky

Name:

Peter Kolchinsky

Title:

Manager