Company: WTFCN
Filing Date: 2025-05-09
Form Type: 424B5
Source: 0001104659-25-046769
Chunk: 10

Company: WINTRUST FINANCIAL CORP
Filing Date: 2025-05-09
Form: 424B5
Chunk 10
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 Bank, and in Canada through our premium finance company, First Insurance Funding of Canada Inc., an indirect subsidiary of Lake Forest Bank, lease financing and other direct leasing opportunities through our wholly-owned subsidiary, Wintrust Asset Finance, Inc., and short-term accounts receivable financing and outsourced administrative services through our wholly-owned subsidiary, Tricom, Inc. of Milwaukee. Further, we provide a full range of wealth management services primarily to customers in our market area through four separate subsidiaries, Wintrust Private Trust Company, N.A. (formerly known as The Chicago Trust Company, N.A.), Wintrust Investments, LLC, Great Lakes Advisors, LLC and Chicago Deferred Exchange Company, LLC.

Our common stock is traded on The NASDAQ Global Select Market under the ticker symbol “WTFC.” Wintrust’s principal executive office is located at 9700 W. Higgins Road, Suite 800, Rosemont, Illinois 60018, and its telephone number is (847) 939-9000.

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TABLE OF CONTENTS

#### Summary of the Offering
The following summary highlights selected information from this prospectus supplement and the accompanying prospectus about the depositary shares and this offering. This description is not complete and does not contain all of the information that you should consider before investing in the depositary shares. You should read this prospectus supplement and the accompanying prospectus, as well as the documents incorporated by reference or deemed to be incorporated by reference herein and therein, carefully before making a decision about whether to invest in the depositary shares. You should pay special attention to the “Risk Factors” section beginning on page S-10of this prospectus supplement and the “Risk Factors” section in our Annual Report on Form 10-K for the year ended December 31, 2024, as such discussion may be further amended or updated in subsequent reports filed by us with the SEC, to determine whether an investment in the depositary shares is appropriate for you. This prospectus supplement includes forward-looking statements that involve risks and uncertainties. For a more complete understanding of the depositary shares, you should read the section entitled “Description of Depositary Shares” beginning on page S-29of this prospectus supplement as well as the section entitled “Description of Capital Stock — Depositary Shares” beginning on page 16of the accompanying prospectus. To the extent the information in this prospectus supplement is inconsistent with the information in the accompanying prospectus, you should rely on the information in this prospectus supplement. As