☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF1934 For the quarterly period ended June 30, 2026OR ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF1934 Commission File Number 1-37728 Donnelley Financial Solutions, Inc.(Exact name of registrant as specified in its charter) (800) 823-5304(Registrant’s telephone number, including area code) Securities registered pursuant to Section 12(b) of the Act: Name of each exchange on which registeredNYSE Indicate by check mark whether the registrant: (1) has filed all reports required to be filed by Sections 13 or 15(d) of theSecurities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to filesuch 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 besubmitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorterperiod that the registrant was required to submit such files). Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, asmaller 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. Large Accelerated filer☒Non-Accelerated filer☐Emerging growth company☐ Smaller reporting company If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition periodfor 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 is a shell company (as defined in Rule 12b-2 of the Exchange Act). As of July 24, 2026, 24,585,383 shares of common stock were outstanding. DONNELLEY FINANCIAL SOLUTIONS, INC.QUARTERLY REPORT ON FORM 10-QFOR THE QUARTERLY PERIOD ENDED JUNE 30, 2026 TABLE OF CONTENTS PageSPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS3Part IFINANCIAL INFORMATIONItem 1:Condensed Consolidated Financial Statements (unaudited)Condensed Consolidated Statements of Operations for the three and six months ended June 30, 2026 and20254Condensed Consolidated Statements of Comprehensive Income for the three and six months ended June 30,2026 and 20255Condensed Consolidated Balance Sheets as of June 30, 2026 and December 31, 20256Condensed Consolidated Statements of Cash Flows for the six months ended June 30, 2026 and 20257Condensed Consolidated Statements of Changes in Stockholders’ Equity for the three and six months endedJune 30, 2026 and 20258Notes to Condensed Consolidated Financial Statements10Item 2:Management’s Discussion and Analysis of Financial Condition and Results of Operations26Item 3:Quantitative and Qualitative Disclosures About Market Risk39Item 4:Controls and Procedures39 Part II OTHER INFORMATIONItem 1:Legal Proceedings39Item 1A:Risk Factors39Item 2:Unregistered Sales of Equity Securities and Use of Proceeds40Item 3:Defaults Upon Senior Securities40Item 4:Mine Safety Disclosures40Item 5:Other Information40Item 6:Exhibits41Signatures42 SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS Donnelley Financial Solutions, Inc. and subsidiaries (“DFIN” or the “Company”) has made forward-looking statements inthis Quarterly Report on Form 10-Q (the “Quarterly Report”) within the meaning of the “safe harbor” provisions of the PrivateSecurities Litigation Reform Act of 1995 that are subject to risks and uncertainties. These statements are based on the beliefs andassumptions of the Company. Generally, forward-looking statements include information concerning possible or assumed futureactions, events, or results of operations of the Company. These statements may include words such as “anticipates,” “estimates,”“expects,” “projects,” “forecasts,” “intends,” “plans,” “continues,” “believes,” “may,” “will,” “goals” and variations of such wordsand similar expressions, and are intended to identify forward-looking statements. Forward-looking statements are not guarantees of future performance. These forward-looking statements are subject to anumber of important factors, including those factors discussed in detail in Part I, Item 1A.Risk Factors,of the Company’s AnnualReport on Form 10-K for the year ended December 31, 2025 filed with the SEC on February 17, 2026 (the “Annual Report”), inaddition to those discussed elsewhere in this Quarterly Report, that could cause the Company’s actual results to differ materiallyfrom those indicated in any such forward-looking statements. These factors include, but are not limited to: •the volatility of the global economy and financial markets, and its impact on transactional volume;•failure to offer