Sunshine Silver Mining & Refining Co

S-11 ny20061035x4_s1.htm S-1

As filed with the Securities and Exchange Commission on May 11, 2026.

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

SUNSHINE SILVER MINING & REFINING COMPANY

(Exact Name of Registrant as Specified in Its Charter)

2209 Big Creek Rd

Kellogg, Idaho 83837

(208) 783-1700

(Address, Including Zip Code, and Telephone Number, Including

Area Code, of Registrant’s Principal Executive Offices)

Heather White

Chief Executive Officer

2209 Big Creek Rd

Kellogg, Idaho 83837

(208) 783-1700

(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent For Service)

Copies to:

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. ☐

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, 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.

The information contained in this preliminary prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED MAY 11, 2026

PRELIMINARY PROSPECTUS

SHARES

SUNSHINE SILVER MINING & REFINING COMPANY

COMMON STOCK

We are selling shares of common stock to the underwriters in a firm commitment offering.

Prior to this offering, there has been no public market for our common stock. We currently estimate that the initial public offering price will be between $ and $ per share. We have applied to list our common stock on the New York Stock Exchange (the “NYSE”) under the symbol “SSMR.”

The underwriters have an option to purchase a maximum of additional shares of common stock from us to cover over-allotments. The underwriters can exercise this option at any time within 30 days from the date of this prospectus.

We are an “emerging growth company” as defined under the federal securities laws and, as such, are subject to certain reduced public company reporting requirements for this prospectus and future filings. See “Prospectus Summary—Implications of Being an Emerging Growth Company.”

The Electrum Group LLC (together with its affiliates, “Electrum”) will control approximately % of the voting power of our common stock upon completion of this offering (or approximately % if the underwriters exercise their option to purchase additional shares of our common stock from us in full). We are, therefore, a “controlled company” within the meaning of the corporate governance standards of the NYSE. As such, we may elect not to comply with certain corporate governance requirements of the NYSE. See “Management—Controlled Company Status.”

Investing in our common stock involves risks. See “Risk Factors” beginning on page 28 of this prospectus.

Delivery of the shares of common stock will be made on or about , 2026 through the book-entry facilities of The Depositary Trust Company.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Joint Lead Book-Running Managers

Joint Bookrunners

The date of this prospectus is , 2026.