Dynamix Corp III

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31,2025

OR

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO

Dynamix Corporation III

(Exact name of Registrant as specified in its Charter)

1980 Post Oak Blvd., Suite 100

PMB 6373

Houston, TX,77056

(Address of principal executive offices, including zip code)

Registrant’s telephone number, including area code:(646) 792 5600

Not Applicable

(Former name or former address, if changed since last report)

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes☐ No ☒

Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. Yes☐ No ☒

Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No☐

Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files). Yes ☒ No☐

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.

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 13(a) of the Exchange Act.☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).☐

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes☒ No☐

The registrant’s Units began trading on the New York Stock Exchange on October 30, 2025 and the registrant’s Class A ordinary shares began separate trading on November 19, 2025.

As of March 18, 2026,20,125,000 Class A ordinary shares, par value $0.0001 per share, and 6,708,333 Class B ordinary shares, par value $0.0001 per share, were issued and outstanding.

Documents Incorporated by Reference: None

TABLE OF CONTENTS

i

Cautionary Note Regarding Forward-Looking Statements

All statements other than statements of historical fact included in this Annual Report on Form 10-K including, without limitation, statements under “Management’s Discussion and Analysis of Financial Condition and Results of Operations” regarding our financial position, business strategy and the plans and objectives of management for future operations, are forward looking statements. When used in this Annual Report on Form 10-K, words such as “may,” “should,” “could,” “would,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “continue,” or the negative of such terms or other similar expressions, as they relate to us or our management, identify forward looking statements. Such forward looking statements are based on the beliefs of management, as well as assumptions made by, and information currently available to, our management. No assurance can be given that results in any forward-looking statement will be achieved and actual results could be affected by one or more factors, which could cause them to differ materially. The cautionary statements made in this Annual Report should be read as being applicable to all forward-looking statements whenever they appear in this Annual Report on Form 10-K. For these statements, we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act. Actual results could differ materially from those contemplated by the forward-looking statements as a result of certain factors, including but not limited to, those detailed in our filings with the Securities and Exchange Commission. All subsequent written or oral forward-looking statements attributable to us or persons acting on our behalf are qualified in their entirety by this paragraph. We maintain a corporate website at https://dynamix3.dynamix-corp.com. The information that may be contained on or accessible through our corporate website or any other website that we may maintain is not incorporated by reference in, or otherwise a part of, this report.

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An investment in our securities involves a high degree of risk. The following is a summary of the principal factors that make an investment in our securities speculative or risky, all of which are more fully described below in the section titled “Risk Factors.” This summary should be read in conjunction with the “Risk Factors” section and should not be relied upon as an exhaustive summary of the material risks facing our business. In addition to the following summary, you should consider the information set forth in the “Risk Factors” section and the other information contained in this Annual Report before investing in our securities.

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