INNOSPEC INC.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

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

For the quarterly period ended March 31,2026

or

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

For the transition period from to

Commission file number 1-13879

INNOSPEC INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (303) 792 5554

Securities registered pursuant to Section 12(b) of the Securities Exchange Act of 1934:

Indicate by check mark whether the registrant (1) has filedall 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 file. Yes ☒No☐

Indicate by check mark whether the registrant is a large acce lerated filer, an accelerated filer, a non-accelerated filer, or 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 standards provided pursuant to Section 13(a) of the Exchange Act.☐

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

Indicate the number of shares outstanding of each ofthe issuer’s classes of common stock, as of the latest practicable date.

TABLE OF CONTENTS

CAUTIONARY STATEMENT RELATIVE TO FORWARD-LOOKING STATEMENTS

This Form 10-Q contains certain “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. All statements other than statements of historical facts included or incorporated herein may constitute forward-looking statements. Such forward-looking statements include statements (covered by words like “expects,” “estimates,” “anticipates,” “may,” “could,” “believes,” “feels,” “plans,” “intends,” “outlook” or similar words or expressions, for example) which relate to earnings, growth potential, operating performance, events or developments that we expect or anticipate will or may occur in the future. Although forward-looking statements are believed by management to be reasonable when made, they are subject to certain risks, uncertainties and assumptions, and our actual performance or results may differ materially from these forward-looking statements. Additional information regarding risks, uncertainties and assumptions relating to Innospec and affecting our business operations and prospects are described in Innospec’s Annual Report on Form 10-K for the year ended December 31, 2025, and other reports filed with the U.S. Securities and Exchange Commission ("SEC"). You are urged to review our discussion of risks and uncertainties that could cause actual results to differ from forward-looking statements under the heading “Risk Factors” in such reports. Innospec undertakes no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.