As filed with the Securities and Exchange Commission on September 30, 2026.

Registration No. 333-299155

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Amendment No. 1

to

FORM S-1/A

REGISTRATION STATEMENT

UNDER THE SECURITIES ACT OF 1933

6400 S. Fiddlers Green Cir., Suite 300

Greenwood Village,Colorado 80111

(800) 401-4535

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

Wesley J. Bolsen, Chief Executive Officer

CitroTech Inc.

6400 S. Fiddlers Green Cir., Suite 300

Greenwood Village, Colorado 80111

(800) 401-4535

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

With Copies to:

APPROXIMATE DATE OF PROPOSED SALE TO PUBLIC: As soon as practicable after this registration statement becomes effective.

If any 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 ☐

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, a 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.

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 registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

EXPLANATORY NOTE

This Amendment No. 1 to the Registration Statement on Form S-1 (File No. 333-299155) is filed solely to amend Item 16 of Part II thereof and to file certain exhibits thereto. This Amendment No. 1 does not modify any provision of the preliminary prospectus contained in Part I. Accordingly, the preliminary prospectus has been omitted.

Item 16. Exhibits and Financial Statement Schedules

(i) Exhibits.

See the Exhibit index on the page immediately preceding the signature page for a list of exhibits filed as part of this registration statement, which Exhibit index is incorporated herein by reference.

(ii) Financial statement schedules.

All financial statement schedules are omitted because they are not required or are not applicable, or the information is otherwise set forth in the consolidated financial statements and related notes thereto.

EXHIBIT INDEX

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Greenwood Village, State of Colorado, on the 30th day of September, 2026.

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

* By: /s/ Wesley J. Bolsen

Wesley J. Bolsen

Attorney-in-fact