As filed with the U.S. Securities and Exchange Commission on September 19, 2025

Registration No. 333- 289849

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Amendment No. 1 to

FORM S-1

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

CALLAN JMB INC.

(Exact name of registrant as specified in its charter)

244 Flightline Drive

Spring Branch, Texas 78070-6241

(830) 438-0395

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

Mr. Wayne Williams
Chief Executive Officer

Callan JMB Inc.

244 Flightline Drive

Spring Branch, Texas 78070-6241

(830) 438-0395

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

Approximate date of commencement of proposed sale to the public: As soon as practicable after this Registration Statement becomes effective.

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. ☐

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 Securities Exchange Act of 1934, as amended (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 comply with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of 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 or until the registration statement shall become effective on such date as the Commission, acting pursuant to such Section 8(a), may determine.

EXPLANATORY NOTE

Callan JMB Inc. is filing this Amendment No. 1 to its Registration Statement on Form S-1 (File No. 333-289849) as an exhibits-only filing. Accordingly, this Amendment consists only of the facing page, this explanatory note, Item 16(a) of the Registration Statement, the signature page to the Registration Statement and filed exhibits. The remainder of the Registration Statement is unchanged and has therefore been omitted.

PART II

INFORMATION NOT REQUIRED IN THE PROSPECTUS

Item 16. Exhibits.

(a) Exhibits.

(b) Financial Statement Schedules.

All financial statement schedules are omitted because the information called for is not required or is shown either in the financial statements or in the notes thereto.

(b) Financial Statement Schedules.

All financial statement schedules are omitted because the information called for is not required or is shown either in the financial statements or in the notes thereto.

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 Spring Branch, Texas, on September 19, 2025.

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.