Andersen Group Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 2025

OR

For the transition period from to

Commission file number 001-43014

Andersen Group Inc.

(Exact name of registrant as specified in its charter)

(415)764-2700

Registrant’s telephone number, including area code

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.

Yeso No x

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.

Yeso No x

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 x Noo

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 x Noo

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 13(a) of the Exchange Act. o

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. o

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. o

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). o

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yeso Nox

The Registrant was not a public company as of the last business day of its most recently completed second fiscal quarter and therefore cannot calculate the aggregate market value of its voting and non-voting common equity held by non-affiliates as of such date. The Registrant’s Class A common stock began trading on the New York Stock Exchange on December 17, 2025.

As of March 20, 2026, there were 12,650,000 shares of the registrant’s Class A common stock, par value $0.0001 and 98,826,563 shares of the registrant’s Class B common stock, par value $0.0001, outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Registrant's definitive proxy statement, or the 2026 Proxy Statement, relating to its annual meeting of stockholders to be held in 2026, or the 2026 Annual Meeting, to be filed with the Securities and Exchange Commission, or the SEC, within 120 days after the end of the fiscal year to which this Annual Report on Form 10-K relates, are incorporated herein by reference where indicated. Except with respect to information specifically incorporated by reference in this Annual Report on Form 10-K, such proxy statement is not deemed to be a part hereof.

TABLE OF CONTENTS

Glossary of Terms

Unless context requires otherwise, references to “we,” “us,” “our,” “Andersen,” or the “Company” in this Annual Report refer to Andersen Group Inc.

•“Aggregator” refers to Andersen Aggregator LLC, a Delaware limited liability company and a holding company of which the equity owners include current Managing Directors.

•“Aggregator LTIP Units” refers to the profits interests of Aggregator. Aggregator LTIP Units are economically similar to stock options. Each Aggregator LTIP Unit has a per unit hurdle price, which is economically similar to the exercise price of a stock option.

•“Andersen Consulting” refers to Andersen Consulting Holdings L.P., a Delaware limited partnership of which Andersen Tax Holdings LLC is the sole member of the general partner of such limited partnership.

•“Andersen Tax Holdings LLC” is a Delaware limited liability company and a holding company of Andersen Tax LLC, a Delaware limited liability company and an operating entity.

•“Andersen Global” refers to Andersen Global, a Swiss verein, of which Andersen Tax LLC is a member.

•“Andersen Group” refers to Andersen Group Inc., a Delaware corporation.

•“Arthur Andersen” refers to the former Arthur Andersen & Co. or Arthur Andersen LLP, as context requires.

•“AT Umbrella” refers to AT Umbrella LLC, a Delaware limited liability company and a direct subsidiary of Andersen Group Inc.

•“CA Notes” refers to notes issued by AT Umbrella LLC to Aggregator with aggregate principal amounts of $187.8 million, equal to the sum of the aggregate principal amounts of the Member Notes, payable over the same two- to seven-year periods, respectively.

•“Class X Aggregator Units” refers to the common interest units in Aggregator, which are designated as Management Class X Aggregator Units and Investment Class X Aggregator Units corresponding to units exchanged in the reorganization transactions from MD Management LLC and MD Investment LLC, respectively.

•“Class X Umbrella Units” refers to the common interest units in AT Umbrella.

•“HO Note” refers to a promissory note in a principal amount of $162.3 million with repayment occurring over an eight-year period relating to payment of the post-service obligations to certain retiring and retired Managing Director members of the Management Holdcos.

•“LTIP Units” refers to the profits interests of AT Umbrella. LTIP Units are economically similar to stock options. Each LTIP Unit has a per unit hurdle price, which is economically similar to the exercise price of a stock option.

•“Management Holdcos” refers to MD Management LLC and MD Investment LLC.

•“Managing Director” refers to a person who holds the title of Managing Director of Andersen Tax LLC, a Delaware limited liability company and an indirect subsidiary of Andersen Group Inc., or a comparable position including certain persons who are members of an advisory board or equivalent of an affiliate of Andersen Tax LLC.

•“Member Notes” refers to promissory notes issued by Management Holdcos to each of their members in a principal amount equal to such member’s and its related transferee's aggregated capital account balance in respect of such Management Holdco as of December 16, 2025, with repayment over a seven-year period for each family of related notes with a principal balance of at least $550,000, either a three- or seven-year period for each family of related notes with a principal balance of less than $550,000 and a period of between two to seven years for notes issued to certain retiring and retired Managing Director members of the Management Holdcos.

•“Reorganization Transactions” refers to a series of internal transactions pursuant to which that Andersen Group Inc. became a holding company whose sole material asset is indirect ownership interests in Andersen Tax Holdings LLC through ownership of Class X Umbrella Units in AT Umbrella LLC.

Special Note Regarding Forward-Looking Statements

This Annual Report on Form 10-K (this Annual Report) includes forward-looking statements that involve substantial risks and uncertainties. All statements other than statements of historical facts contained in this Annual Report, including statements regarding our future operating results and financial position, our business strategy and plans, market growth, and our objectives for future operations, are forward-looking statements. The words “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “design,” “intend,” “expect,” “could,” “plan,” “potential,” “predict,” “seek,” “should,” “would,” or the negative version of these words and similar expressions are intended to identify forward-looking statements. We have based these forward-looking statements on our current expectations and projections about future events and trends that we believe may affect our financial condition, results of operations, strategy, short- and long-term business operations and objectives, and financial needs. Forward-looking statements contained in this Annual Report include, but are not limited to, statements about:

•our future revenue and operating expenses;

•the demand for our services;

•our ability to acquire new clients and successfully retain existing clients;

•our ability to comply with laws and regulations that currently apply or become applicable to our business both in the United States and internationally, including but not limited to, privacy and data security laws and regulations;

•our reliance on key personnel and our ability to identify, recruit, and retain skilled personnel;

•our plans to expand our business, whether through acquisitions of businesses, business combinations with businesses, introduction of new services or otherwise;

•our ability to maintain our culture;

•our ability to effectively integrate or manage our acquisitions and business combinations;

•competition in the markets in which we operate;

•our ability to protect against or mitigate the effects of cyberattacks or other breaches of our data;

•the effects of natural disasters, man-made problems, and similar events on our business;

•general economic conditions in the United States and globally, including the effects of global geopolitical conflicts, inflation, tariffs, interest rates, any instability in the global banking sector, and foreign currency exchange rates;

•our ability to grow our business in light of macroeconomic uncertainty;

•the risks related to our Class A common stock and our dual-class common stock structure;

•our ability to remediate our material weaknesses in our internal control over financial reporting;

•our future financial performance, including our expectations regarding our revenue, cost of revenue, operating expenses, key metrics and our ability to achieve and maintain future profitability;

•our business model;

•our ability to effectively manage our growth and expand our operations;

•our market opportunity and anticipated trends in our business and industry;

•our ability to remain competitive as we continue to scale our business;

•our expectations regarding our ability to obtain, maintain, enforce, defend and enhance our intellectual property rights;

•the amount and timing of any payments under the Tax Receivable Agreement;

•increased expenses associated with being a public company; and

•other statements regarding our future operations, financial condition, prospects and business strategies.

We caution you that the foregoing list may not contain all of the forward-looking statements made in this Annual Report.

These forward-looking statements are subject to a number of risks, uncertainties, and assumptions, including those described in Part I, Item 1A “Risk Factors”. Moreover, we operate in a very competitive and rapidly changing environment. New risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. In light of these risks, uncertainties, and assumptions, the forward-looking events and circumstances discussed in this Annual Report may not occur and actual results could differ materially and adversely from those anticipated or implied in the forward-looking statements.

You should not rely upon forward-looking statements as predictions of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee future results, performance or achievements. The forward-looking statements made in this Annual Report are given only as of the date on which the statements are made. We undertake no obligation to update any of these forward-looking statements for any reason after the date of this Annual Report or to conform these statements to actual results or to changes in our expectations, except as required by law.

In addition, statements that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this Annual Report, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into or review of all potentially available relevant information. These statements are inherently uncertain and investors are cautioned not to unduly rely upon these statements.

You should read this Annual Report and the documents that we reference in this Annual Report and have filed with the SEC as exhibits to this Annual Report with the understanding that our actual future results, performance, and events and circumstances may be materially different from what we expect.