Washington, D.C. 20549 Five9, Inc. Indicate by check mark whether the registrant: (1)has filed all reports required to be filed by Section13 or 15(d) of the Securities ExchangeAct 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 subjectto 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 toRule 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 tosubmit such files).Yes:☒No:☐ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reportingcompany, or an emerging growth company. See definitions of “large accelerated filer,” “accelerated filer”, “smaller reporting company”, and“emerging growth company” in Rule12b-2 of the Exchange Act. Large accelerated filer☒Non-accelerated filer☐ Acceleratedfiler☐Smallerreportingcompany☐Emerging growth company☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complyingwith any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.Yes:☐No:☐ Indicate by check mark whether the registrant is a shell company (as defined in Rule12b-2 of the ExchangeAct).Yes:☐No:☒ As of July31, 2026, there were 74,723,531 shares of the Registrant’s common stock, par value $0.001 per share, outstanding. FIVE9, INC. FORM 10-Q PART I. FINANCIAL INFORMATION ITEM1. Financial StatementsCondensed Consolidated Balance Sheets (Unaudited)Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited)Condensed Consolidated Statements of Stockholders’ Equity (Unaudited)Condensed Consolidated Statements of Cash Flows (Unaudited)Notes to Condensed Consolidated Financial Statements (Unaudited)ITEM 2. Management’s Discussion and Analysis of Financial Condition and Results of OperationsOverviewKey Operating and Non-GAAP Financial Performance MetricsKey Components of Our Results of OperationsResults of Operations for the Three and Six Months Ended June 30, 2026 and 2025Liquidity and Capital ResourcesCritical Accounting Policies and EstimatesRecent Accounting PronouncementsContractual and Other ObligationsITEM 3. Quantitative and Qualitative Disclosures about Market RiskITEM 4. Controls and Procedures PART II. OTHER INFORMATION ITEM 1. Legal ProceedingsITEM 1A. Risk FactorsITEM 2. Unregistered Sales of Equity Securities and Use of ProceedsITEM 3. Defaults Upon Senior SecuritiesITEM 4. Mine Safety DisclosuresITEM 5. Other InformationITEM 6. Exhibits SIGNATURES SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS This Quarterly Report on Form 10-Q contains forward-looking statements within the meaning of Section 27A of the SecuritiesAct of 1933 and Section 21E of the Securities Exchange Act of 1934, which involve substantial risks and uncertainties. Thesestatements reflect the current views of our senior management with respect to future events, strategies and financial trends andperformance. These forward-looking statements include statements with respect to our business, expenses, strategies, losses, growthplans, product and customer initiatives, market growth projections, and our industry, including those set forth under “Management’sDiscussion and Analysis of Financial Condition and Results of Operations” and elsewhere in this Quarterly Report. Statements thatinclude the words “expect,” “intend,” “plan,” “believe,” “project,” “forecast,” “estimate,” “may,” “should,” “anticipate” and similarstatements of a future or forward-looking nature identify forward-looking statements for purposes of the federal securities laws orotherwise. Forward-looking statements address matters that involve risks and uncertainties. Accordingly, there are or will be importantfactors that could cause our actual results to differ materially from those indicated in these statements. These factors include theinformation set forth under the caption "Risk Factors" set forth in Part 1, Item 1A, of our Annual Report on Form 10-K for the fiscalyear ended December 31, 2025, which we encourage you to carefully read, and include the following: •adverse economic conditions, including new and continued macroeconomic challenges resulting from the impact of globaltariff increases and potential future increases and announcements regarding same, as well as the impact of current andpotential global conflicts, continued inflation, uncertainty regarding consumer spending, high interest rates, fluctuations incurrency rates, and other factors, may harm our business;•if we are unable to attract new customers or sell additional services and functionality to our existing customers, our revenueand reven