SEI Investments Co

________________________________________ 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.)

PART I - FINANCIAL INFORMATION Page Item 1. Financial Statements. 2 Consolidated Balance Sheets (Unaudited) -- September 30, 2026 and December 31, 2025 2 Consolidated Statements of Operations (Unaudited) -- For the Three and Nine Months Ended September 30, 2026 and 2025 4 Consolidated Statements of Comprehensive Income (Unaudited) -- For the Three and Nine Months Ended September 30, 2026 and 2025 5 Consolidated Statements of Changes in Equity (Unaudited) -- For the Three and Nine Months Ended September 30, 2026 and 2025 6 Consolidated Condensed Statements of Cash Flows (Unaudited) -- For the Nine Months Ended September 30, 2026 and 2025 8 Notes to Consolidated Financial Statements 10 Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations. 35 Item 3. Quantitative and Qualitative Disclosures About Market Risk. 52 Item 4. Controls and Procedures. 52

PART II - OTHER INFORMATION Item 1. Legal Proceedings. 54 Item 1A. Risk Factors. 54 Item 2. Unregistered Sales of Equity Securities and Use of Proceeds. 54 Item 5. Other Information 54 Item 6. Exhibits. 55 Signatures 56

PART I - FINANCIAL INFORMATION Item 1. Financial Statements.

Consolidated Balance Sheets SEI Investments Company (unaudited) and Subsidiaries (Dollars in thousands, except per-share data)

September 30, 2026 December 31, 2025 Assets Current Assets: Cash and cash equivalents $ 399,766 $ 399,804 Receivables from investment products 59,278 63,317 Receivables, net of allowance for doubtful accounts of $ 2,398 and $ 1,916 851,279 709,748 Securities owned 25,750 33,777 Other current assets 75,611 66,691 Total Current Assets 1,411,684 1,273,337 Property and Equipment, net of accumulated depreciation of $ 487,903 and $ 468,700 153,496 150,434 Operating Lease Right-of-Use Assets 30,186 26,447 Capitalized Software, net of accumulated amortization of $ 697,165 and $ 669,896 224,189 234,272 Investments 335,895 428,004 Assets of Consolidated Variable Interest Entities 223,785 183,994 Goodwill 392,205 354,989 Intangible Assets, net of accumulated amortization of $ 78,925 and $ 49,534 481,727 368,272 Deferred Contract Costs 58,954 53,345 Deferred Income Taxes 9,178 8,048 Deposits Related to Acquisitions 33,005 118,606 Other Assets, net 80,335 60,096 Total Assets $ 3,434,639 $ 3,259,844

The accompanying notes are an integral part of these consolidated financial statements.

Consolidated Balance Sheets SEI Investments Company (unaudited) and Subsidiaries (Dollars in thousands, except per-share data)

September 30, 2026 December 31, 2025 Liabilities, Redeemable Non-controlling Interests and Equity Current Liabilities: Accounts payable $ 13,905 $ 5,404 Accrued liabilities 284,920 359,823 Current portion of long-term debt 5,754 - Current portion of long-term operating lease liabilities 9,124 8,677 Deferred revenue 13,648 13,307 Total Current Liabilities 327,351 387,211 Long-term Debt 30,951 - Liabilities of Consolidated Variable Interest Entities 136,536 108,504 Deferred Income Taxes 14,206 16,842 Long-term Operating Lease Liabilities 23,474 19,885 Other Long-term Liabilities 24,823 23,626 Total Liabilities 557,341 556,068 Commitments and Contingencies Redeemable Non-controlling Interests 323,105 243,959 Equity: Shareholders' Equity: Common stock, $ 0.01 par value, 750,000,000 shares authorized; 118,942,181 and 122,232,251 shares issued and outstanding 1,189 1,222 Capital in excess of par value 1,758,970 1,678,787 Retained earnings 785,633 792,280 Accumulated other comprehensive loss, net ( 33,229 ) ( 24,505 ) Total SEI Shareholders' Equity 2,512,563 2,447,784 Non-controlling interests 41,630 12,033 Total Equity 2,554,193 2,459,817 Total Liabilities, Redeemable Non-controlling Interests and Equity $ 3,434,639 $ 3,259,844

The accompanying notes are an integral part of these consolidated financial statements.

Consolidated Statements of Operations SEI Investments Company (unaudited) and Subsidiaries (Dollars in thousands, except per-share data)

Three Months Ended September 30, Nine Months Ended September 30, 2026 2025 2026 2025 Revenues: Asset management, administration and distribution fees $ 531,417 $ 461,964 $ 1,542,883 $ 1,331,650 Information processing and software servicing fees 130,626 116,547 382,960 357,806 Total revenues 662,043 578,511 1,925,843 1,689,456 Expenses: Subadvisory, distribution and other asset management costs 61,194 55,072 177,920 152,313 Software royalties and other information processing costs 9,878 9,434 29,487 27,706 Compensation, benefits and other personnel 220,069 203,739 634,223 594,097 Stock-based compensation 16,000 13,956 46,809 41,985 Consulting, outsourcing and professional fees 58,394 54,401 169,066 167,344 Data processing and computer related 49,388 41,569 141,123 122,689 Facilities, supplies and other costs 22,318 20,982 64,093 61,481 Amortization 19,684 11,912 57,175 33,071 Depreciation 7,119 7,485 21,446 23,077 Total expenses 464,044 418,550 1,341,342 1,223,763 Income from operations 197,999 159,961 584,501 465,693 Net gain from investments 1,206 1,992 4,387 4,244 Interest and dividend income 6,866 10,207 21,040 29,711 Interest expense ( 606 ) ( 109 ) ( 1,641 ) ( 386 ) Gain on sale of business