Exhibit 5.1

[WILSON SONSINI GOODRICH & ROSATI LETTERHEAD]

January 22, 2015

SVB Financial Group

3003 Tasman Drive

Santa Clara, CA 95054-1191

Re: Registration Statement on Form S-3

Ladies and Gentlemen:

At your request, we have examined the Registration Statement on Form S-3 (the “Registration Statement”), filed by SVB Financial Group, a Delaware corporation (the “Company”), with the Securities and Exchange Commission (the “Commission”) in connection with the registration pursuant to the Securities Act of 1933, as amended (the “Act”), of the Debt Securities (as defined below).

The Registration Statement relates to the proposed issuance and sale by the Company, from time to time, pursuant to Rule 415 under the Act, as set forth in the Registration Statement, the prospectus contained therein (the “Prospectus”) and the supplements to the prospectus referred to therein (each a “Prospectus Supplement”), of the Company’s senior debt securities (the “Debt Securities”).

The Debt Securities are to be sold from time to time as set forth in the Registration Statement, the Prospectus contained therein and the Prospectus Supplements. The Debt Securities are to be issued pursuant to the indenture dated September 20, 2010, by and between the Company and U.S. Bank National Association, as trustee (the “Trustee”), a copy of which is filed as Exhibit 4.1 to the Current Report on Form 8-K filed on September 20, 2010, as such indenture may be supplemented from time to time (the “Indenture”). The Debt Securities are to be sold pursuant to a purchase, underwriting, subscription or similar agreement in substantially the form to be filed under a Current Report on Form 8-K. The Debt Securities are to be issued in the forms set forth in the Indenture. The Indenture may be supplemented, as applicable, in connection with the issuance of each such series of Debt Securities, by a supplemental indenture or other appropriate action of the Company creating such series of Debt Securities.

We have examined such instruments, documents and records we deemed relevant and necessary for the basis of the opinions we hereinafter express. In such examination, we have assumed (a) the authenticity of original documents and the genuineness of all signatures, (b) the conformity to the originals of all documents submitted to us as copies, (c) the truth, accuracy and completeness of the information, representations and warranties contained in the records, documents, instruments and certificates we have reviewed, (d) the Registration Statement, and any amendments thereto (including post-effective amendments), will have become effective under the Act, (e) a prospectus supplement will have been filed with the Securities and Exchange Commission describing the securities offered thereby, (f) all securities will be issued and sold in compliance with applicable federal and state securities laws and in the manner stated in the Registration Statement and the applicable prospectus supplement, (g) a definitive purchase, underwriting or similar agreement with respect to any securities offered will have been duly authorized and validly executed and delivered by the Company and the other parties thereto, and (h) any securities issuable upon conversion, exchange, redemption or exercise of any securities being offered will be duly authorized, created and, if appropriate, reserved for issuance upon such conversion, exchange, redemption or exercise.

Based on such examination, we are of the opinion that:

1. With respect to Debt Securities to be issued under the Indenture, when: (a) the Company has validly executed and delivered an officers’ certificate pursuant to the Indenture setting forth the terms of the Debt

Securities to the Trustee; (b) the Board of Directors of the Company (the “Board”) has taken all necessary corporate action to approve the issuance and terms of such Debt Securities, the terms of the offering thereof and related matters; and (c) such Debt Securities have been duly executed, authenticated, issued and delivered as contemplated by the Registration Statement, the Prospectus and the related Prospectus Supplement and in accordance with the provisions of the Indenture and the applicable definitive purchase, underwriting or similar agreement approved by the Board, such Debt Securities will be validly issued and will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their terms.

Our opinion that any document is legal, valid and binding is qualified as to:

(a) limitations imposed by bankruptcy, insolvency, reorganization, arrangement, fraudulent conveyance, moratorium or other similar laws relating to or affecting the rights of creditors generally, including, without limitation, laws relating to fraudulent transfers or conveyances and preferences;

(b) rights to indemnification and contribution, which may be limited by applicable law or equitable principles; and

(c) general principles of equity, including without limitation concepts of materiality, reasonableness, good faith and fair dealing, the effect of judicial discretion and possible unavailability of specific performance, injunctive relief or other equitable relief, and limitations on rights of acceleration, regardless of whether such enforceability is considered in a proceeding in equity or at law.

We express no opinion as to the laws of any other jurisdiction, other than the Federal laws of the United States of America, the State of New York as to the enforceability of the Debt Securities and the General Corporation Law of the State of Delaware (the “DGCL”).

We hereby consent to the filing of this opinion as an exhibit to the above-referenced Registration Statement and to the use of our name wherever it appears in the Registration Statement, the Prospectus, any Prospectus Supplement, and in any amendment or supplement thereto. In giving such consent, we do not believe that we are “experts” within the meaning of such term as used in the Act or the rules and regulations of the Commission issued thereunder with respect to any part of the Registration Statement, including this opinion as an exhibit.

Sincerely,

WILSON SONSINI GOODRICH & ROSATI

Professional Corporation

/s/ Wilson Sonsini Goodrich & Rosati