UMB FINANCIAL CORP

On September 5, 2025, three foundations and trusts that are related interests of Chairman and Chief Executive Officer J. Mariner Kemper adopted a single, pre-arranged stock sale plan in accordance with Rule 10b5-1(c) (Rule 10b5-1) under the Exchange Act for the sale of shares of the Company’s common stock (the 2026 Plan). The 2026 Plan was entered into during an open trading window in accordance with the Company’s requirements regarding transactions in the Company’ssecuritiesand is intended to satisfy the affirmative defense conditions of Rule 10b5-1.

The 2026 Plan provides for the monthly sale of an initial number of shares of the Company’s common stock once the market price of the Company’s common stock meets or exceeds certain minimum threshold prices as specified in the 2026 Plan. Should the market price of the Company’s shares meet or exceed secondary and tertiary pricing thresholds as specified in the 2026 Plan, up to one and a half and double the initial number of shares in the aggregate may be sold in that month, respectively. Sales under the 2026 Plan may occur beginning in January of 2026 (after conclusion of the applicable cooling off period following adoption of the 2026 Plan) and end no later than December 31, 2026. The aggregate number of shares of common stock of the Company that will be available for sale under the 2026 Plan will vary depending on the market price achieved but will not exceed a maximum of 105,024 shares in aggregate.