SEI Investments Co

For the transition period from _________ to ________

Commission File Number: 0-10200 ________________________________________ ________________________________________ SEI INVESTMENTS COMPANY (Exact name of Registrant as Specified in Its Charter) Pennsylvania 23-1707341 State or Other Jurisdiction of Incorporation or Organization I.R.S. Employer Identification No.

Common Stock, $.01 par value 122,248,132

DOCUMENTS INCORPORATED BY REFERENCE Portions of the following documents are incorporated by reference herein:

1. The definitive proxy statement relating to the registrant's 2026 Annual Meeting of Shareholders, to be filed within 120 days after the end of the fiscal year covered by this annual report, is incorporated by reference in Part III hereof.

SEI INVESTMENTS COMPANY Fiscal Year Ended December 31, 2025 TABLE OF CONTENTS Page PART I Item 1. Business. 2 Item 1A. Risk Factors. 9 Item 1B. Unresolved Staff Comments. 20 Item 1C. Cybersecurity. 20 Item 2. Properties. 21 Item 3. Legal Proceedings. 22 Item 4. Mine Safety Disclosures. 22

PART II Item 5. Market for Registrant's Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities. 23 Item 6. [Reserved] 24 Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations. 25 Item 7A. Quantitative and Qualitative Disclosures About Market Risk. 40 Item 8. Financial Statements and Supplementary Data. 41 Item 9. Changes in and Disagreements With Accountants on Accounting and Financial Disclosure. 89 Item 9A. Controls and Procedures. 89 Item 9B. Other Information. 89 Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections. 89

PART III Item 10. Directors, Executive Officers and Corporate Governance. 90 Item 11. Executive Compensation. 90 Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters. 91 Item 13. Certain Relationships and Related Transactions, and Director Independence. 91 Item 14. Principal Accounting Fees and Services. 91

PART IV Item 15. Exhibits and Financial Statement Schedules. 91 Item 16. Form 10-K Summary. 91

streamlines alternative investment access and processing for advisors and institutions, supporting the growing demand for private market solutions. • Scaled, front‑to‑back capabilities for complex managers and private markets. SEI provides global fund administration, depositary, and middle‑office services and has distinctive strength serving large, multi‑strategy and private credit managers, benefiting from the continued shift from insourcing to outsourcing and expansion in retail‑accessible alternative structures (interval funds and Business Development Companies) and Collective Investment Trusts (CITs). • Trust‑based custody integrated with modern wealth technology. Through SEI Private Trust Company (SPTC), client assets are held in the client's name (no commingling, pledging, or margining), tightly integrated with the SEI Wealth Platform SM to deliver an end‑to‑end, single‑infrastructure experience and multi‑custody data fidelity. • Commitment to security, data, and AI. SEI invests heavily in cybersecurity, cloud infrastructure, and data analytics. The SEI Data Cloud, digital workflows, and embedded AI/automation tools drive operational efficiency, enhance reporting, and support scalable growth for clients. • Strong, long-term client relationships. SEI's client base includes leading banks, registered investment advisors (RIAs), institutional investors, and alternative managers, many of whom have partnered with SEI for decades. The firm's focus on enterprise relationships and wallet share expansion is driving growth across segments. Our clients include wealth managers, banks, investment advisors, asset managers, family offices, institutional investors, and ultra-high-net-worth investors. For the Year Ended December 31, 2025 (all dollar amounts in thousands) Investment Managers Private Banks Investment Advisors Institutional Investors Investments in New Businesses Total Investment Technology & Operations $ 773,262 $ 407,909 $ 98,143 $ 9,525 $ 15,380 $ 1,304,219 Asset Management 602 137,247 455,246 262,122 21,967 877,184 Professional Services & Other 41,141 27,783 24,008 10,851 12,195 115,978 Total Revenues $ 815,005 $ 572,939 $ 577,397 $ 282,498 $ 49,542 $ 2,297,381

Technology and operations We provide the technology and operational infrastructure across the front, middle, and back office to help our clients scale, increase efficiency, and improve performance. Capabilities include: • Business process outsourcing and custody; • Fund administration, depositary services, investment accounting, and investor servicing; • Curated suite of internally managed and third-party investment products, including ETFs, SMAs, and UMAs; • Investment expertise in direct indexing, factor-based, alternatives, and tax management; • Discretionary investment management for institutions in need of expertise, infrastructure and enhanced governance; • Data and information management, analytics, and reporting; • Regulatory and compliance service; and • Network operations, cloud, and cybersecurity services. Our proprietary technology platforms include the SEI Wealth Platform SM (SWP)