INNIO Holding GmbH

S-11 ck0002109150-20260511.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

INNIO Holding GmbH*

(Exact name of registrant as specified in its charter)

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

INNIO Holding Inc.

1101 W. St. Paul Ave.

Waukesha, WI 53188

+1.262.547.3311

(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 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, 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 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.

(*) We intend to convert the legal form of our company from a German limited liability company (Gesellschaft mit beschränkter Haftung) to a Dutch private company with limited liability (besloten vennootschap met beperkte aansprakelijkheid) and then to a Dutch public company (naamloze vennootschap) under Dutch law and to change our name from INNIO Holding GmbH to INNIO Group Holding B.V. and then to INNIO N.V. prior to the closing of this offering.

The information contained in this preliminary prospectus is not complete and may be changed. These securities may not be sold 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 is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Subject to Completion, Dated , 2026

PRELIMINARY PROSPECTUS

to be converted into and renamed

INNIO N.V.

This is the initial public offering of the common shares of INNIO Holding GmbH (to be converted into and renamed INNIO N.V.). We are offering common shares, nominal value EUR per common share. The selling shareholders identified in this prospectus are selling common shares. We will not receive any proceeds from the sale of the common shares by the selling shareholders in this offering.

Prior to this offering, there has been no public market for our common shares. It is currently estimated that the initial public offering price will be between $ and $ per common share.

We have applied to list our common shares on the Nasdaq Global Select Market (“Nasdaq”) under the symbol “INIO.”

Immediately following the completion of this offering, AI Alpine (Luxembourg) S.à r.l. (our “Principal Shareholder”), which will be a selling shareholder in this offering, will hold an aggregate of common shares, representing approximately % of the voting power of our outstanding share capital, assuming no exercise of the underwriters’ option to purchase additional common shares. As a result, following this offering we will be a “controlled company” within the meaning of the corporate governance rules of Nasdaq. For additional information, see the section titled “Management—Controlled Company.”

Investing in our common shares involves risks. See the section titled “Risk Factors” beginning on page 26 to read about factors you should consider before deciding to invest in our common shares.

Neither the Securities and Exchange Commission (the “SEC”) nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

(1) See the section titled “Underwriting” for a description of the compensation payable to the underwriters.

The selling shareholders have granted the underwriters an option to purchase up to an additional common shares from them at the initial public offering price, less underwriting discounts and commissions. We will not receive any proceeds from the sale of such additional common shares by the selling shareholders.

The underwriters expect to deliver the shares against payment in New York, New York on or about , 2026.

*listed in alphabetical order

Prospectus dated , 2026

TABLE OF CONTENTS

You should rely only on the information contained in this prospectus and any free writing prospectus prepared by or on behalf of us that we have referred to you. Neither we, the selling shareholders, nor the underwriters have authorized anyone to provide you with additional or different information. If anyone provides you with additional, different or inconsistent information, you should not rely on it. Offers to sell, and solicitations of offers to buy, our common shares are being made only in jurisdictions where offers and sales are permitted. The information contained in this prospectus is accurate only as of the date of this prospectus, regardless of the time of delivery of this prospectus or of any sale of our common shares. Our business, financial condition, operating results and prospects may have changed since such date.

For investors outside the United States: Neither we, the selling shareholders, nor any of the underwriters have done anything that would permit this offering or possession or distribution of this prospectus in any jurisdiction where action for that purpose is required, other than in the United States. Persons outside of the United States who come into possession of this prospectus must inform themselves about, and observe any restrictions relating to, this offering of our common shares and the distribution of this prospectus outside of the United States.

About this Prospectus

Prior to the closing of this offering, we will complete a corporate reorganization described in more detail under “Corporate Reorganization,” in the course of which we will be converted into a Dutch private company (besloten vennootschap met beperkte aansprakelijkheid), and our legal name will change to INNIO Group Holding B.V. We will then be converted into a public company under Dutch law (naamloze vennootschap), and our legal name will change to INNIO N.V. (the “Reorganization”).

As used in this prospectus, unless the context otherwise indicates, any reference to the “Group,” “INNIO,” “our Company,” “us,” “we,” and “our” refers to (i) INNIO Holding GmbH, incorporated under the laws of Germany, together with its consolidated subsidiaries, prior to the completion of its conversion into INNIO Group Holding B.V. (the “Conversion”), (ii) INNIO Group Holding B.V. together with its consolidated subsidiaries, as of the completion of the Conversion and (iii) INNIO N.V. and its consolidated subsidiaries after the completion of the Reorganization.

Certain monetary amounts, percentages and other figures included in this prospectus have been subject to rounding adjustments. Percentage amounts included in this prospectus have not in all cases been calculated on the basis of such rounded figures, but on the basis of such amounts prior to rounding. For this reason, percentage amounts in this prospectus may vary from those obtained by performing the same calculations using the figures in our consolidated financial statements included elsewhere in this prospectus. Certain other amounts that appear in this prospectus may not sum due to rounding.

Financial information presented in parentheses denotes the negative of such number presented. A dash (“–”) signifies that the relevant figure is not available or zero, while a zero (“0.0”) signifies that the relevant figure has been rounded to zero.

Compression metrics in this prospectus have been converted from horsepower to megawatts for consistency across metrics.

Basis of Presentation

Except as otherwise disclosed in this prospectus, the historical consolidated financial statements, the summary historical consolidated financial data and the other financial information included elsewhere in this prospectus have been prepared in U.S. dollars in accordance with accounting principles generally accepted in the United States (“GAAP”). This historical financial information does not give effect to this offering.

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