UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 8-K

CURRENT REPORT

Pursuant To Section 13 OR 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): September 27, 2017

STIFEL FINANCIAL CORP.

(Exact name of registrant as specified in its charter)

One Financial Plaza

501 North Broadway

St. Louis, Missouri 63102-2102

(Address of principal executive offices, including zip code)

Registrant’s telephone number, including area code: (314) 342-2000

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

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 complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐

Item 1.01    Entry into a Material Definitive Agreement.

On September 27, 2017, Stifel Financial Corp. (the “Company”) entered into an Underwriting Agreement (the “Underwriting Agreement”) with Keefe, Bruyette & Woods, Inc., Merrill Lynch, Pierce, Fenner & Smith Incorporated and Morgan Stanley & Co. LLC (the “Representatives”), as representatives of the underwriters named in Schedule A thereto (the “Underwriters”), providing for, among other things, the sale by the Company and the purchase by the Underwriters, acting severally and not jointly, of $200,000,000 aggregate principal amount of the Company’s 5.20% Senior Notes due 2047 (the “Notes”). The Company has granted to the Underwriters an option, exercisable for 30 days, to purchase up to an additional $30,000,000 principal amount of the Notes from us, at the public offering price less the underwriting discount, to cover overallotments, if any.

The Notes are registered for offer and sold pursuant to an effective Registration Statement on Form S-3 (File No. 333-219926), which was declared effective by the Securities and Exchange Commission (“SEC”) on August 17, 2017 (the “Registration Statement”).

The foregoing description of the Underwriting Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Underwriting Agreement, a copy of which is attached to this Current Report on Form 8-K as Exhibit 1.1 and is incorporated by reference herein and into the Registration Statement.

Item 8.01    Other Events.

In connection with the offering of the Notes, as described in response to Item 1.01, the Company is filing this Current Report on Form 8-K to add the following exhibit to the Registration Statement: (i) the Underwriting Agreement (Exhibit 1.1 to this Current Report on Form 8-K).

Cautionary Note Regarding Forward-Looking Statements

This Current Report on Form 8-K contains certain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended that are based upon the Company’s current expectations and projections about future events. The Company intends for these forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995, and the Company is including this statement for purposes of these safe harbor provisions. The forward-looking statements are subject to risks and uncertainties that could cause actual results to differ materially from those expressed in or implied by the statements. In addition, the Company’s past results of operations do not necessarily indicate the Company’s future results. Factors that may cause actual results to differ materially from those contemplated by such forward-looking statements include: the ability to successfully integrate acquired companies or the branch offices and financial advisors; a material adverse change in the Company’s financial condition; the risk of borrower, depositor and other customer attrition; a change in general business and economic conditions; changes in the interest rate environment, deposit flows, loan demand, real estate values and competition; changes in accounting principles, policies or guidelines; changes in legislation and regulation; other economic, competitive, governmental, regulatory, geopolitical and technological factors

affecting the Company’s operations, pricing and services. Forward-looking statements speak only as to the date they are made. The Company does not undertake to update forward-looking statements to reflect circumstances or events that occur after the date the forward-looking statements are made. The Company disclaims any intent or obligation to update these forward-looking statements.

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EXHIBIT INDEX

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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