Additional Securities Registration Statement (Form S-1MEF)

As filed with the Securities and Exchange Commission on June 17, 2026.

Registration No. 333-296236

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Kardigan, Inc.

(Exact name of registrant as specified in its charter)

Delaware		2834		99-2994203
(State or other jurisdiction of incorporation or organization)		(Primary Standard Industrial Classification Code Number)		(I.R.S. Employer Identification No.)

Kardigan, Inc.

506 Carnegie Center Drive, Suite 201

Princeton, NJ 08540

(415) 573-3220

(Address, including zip code, and telephone number, including area code, of registrant's principal executive offices)

Tassos Gianakakos

Chief Executive Officer

Kardigan, Inc.

506 Carnegie Center Drive, Suite 201

Princeton, NJ 08540

(415) 573-3220

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Mitchell S. Bloom Benjamin K. Marsh Janet Hsueh Goodwin Procter LLP 100 Northern Avenue Boston, MA 02210 (617) 570-1000		Peter N. Handrinos Elisabeth M. Martin Latham & Watkins LLP 200 Clarendon Street Boston, MA 02116 (617) 880-4500

Approximate date of commencement of proposed sale to the public: As soon as practicable after the effective date of this registration statement.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box: ☐

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☒ (333-296236)

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company" and "emerging growth company" in Rule 12b-2 of the Exchange Act.

Large accelerated filer		☐		Accelerated filer		☐
Non-accelerated filer		☒		Smaller reporting company		☒
				Emerging growth company		☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

The Registration Statement shall become effective upon filing in accordance with Rule 462(b) promulgated under the Securities Act of 1933, as amended.

EXPLANATORY NOTE AND INCORPORATION BY REFERENCE

This Registration Statement is being filed pursuant to Rule 462(b) under the Securities Act of 1933, as amended (the "Securities Act"), for the sole purpose of increasing the aggregate number of shares of common stock offered by Kardigan, Inc. (the "Registrant") by 1,916,666 shares, 250,000 of which are subject to purchase upon exercise of the underwriters' option to purchase additional shares of the Registrant's common stock. The contents of the Registration Statement on Form S-1, as amended (File No. 333-296236), filed by the Registrant with the Securities and Exchange Commission (the "Commission") pursuant to the Securities Act, including all amendments and exhibits thereto (the "Prior Registration Statement"), which was declared effective by the Commission on June 17, 2026, are incorporated by reference into this Registration Statement.

The additional shares of common stock that are being registered for issuance and sale are in an amount and at a price that together represent no more than 20% of the maximum aggregate offering price set forth in Exhibit 107 of the Prior Registration Statement.

The required opinion and consents are listed on an Exhibit Index attached hereto and filed herewith or incorporated by reference herein.

EXHIBIT INDEX

Exhibit No.		Exhibit Index
5.1		Opinion of Goodwin Procter LLP
23.1		Consent of PricewaterhouseCoopers LLP, Independent Registered Public Accounting Firm
23.2		Consent of Goodwin Procter LLP (included in Exhibit 5.1)
24.1*		Power of Attorney
107		Filing Fee Table

*	Previously included on the signature page to the Prior Registration Statement, originally filed with the Securities and Exchange Commission on May 26, 2026 and incorporated by reference herein.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the Municipality of Princeton, New Jersey, on the 17 day of June, 2026.

Kardigan, Inc.
By:		/s/ Tassos Gianakakos
		Tassos Gianakakos
		Chief Executive Officer, Director, and Chair

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed by the following persons in their capacities and on the date indicated.

Signature		Title
/s/ Tassos Gianakakos Tassos Gianakakos		Chief Executive Officer, Director, and Chair (Principal Executive Officer)
/s/ Brianne Puglisi Brianne Puglisi		Chief Financial Officer (Principal Financial Officer and Principal Accounting Officer)
* Paul Berns		Director
* David Meeker, M.D.		Director
* Douglas Giordano		Director
* Kim Popovits		Director
* Tim Walbert		Director

*By:		/s/ Tassos Gianakakos
		Tassos Gianakakos
		Attorney-in-Fact