Exhibit 5.1

January 7, 2009

SVB Financial Group

3003 Tasman Drive

Santa Clara, CA 95054-1191

Re: Registration Statement on Form S-3

Ladies and Gentlemen:

We have acted as counsel to SVB Financial Group, a Delaware corporation (the “Company”), in connection with a Registration Statement on Form S-3 (the “Registration Statement”) to be filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), for the registration of (a) 235,000 shares of Fixed Rate Cumulative Perpetual Preferred, Series B, par value $.001 per share (the “Preferred Shares”); (b) a warrant dated December 12, 2008 (the “Warrant”) to purchase common stock, $.001 par value per share, of the Company (the “Common Stock”); and (c) the 708,116 shares of Common Stock for which the Warrant may be exercised (the “Warrant Shares,” and together with the Preferred Shares and the Warrant, collectively, the “Securities”). All of the Securities are being registered on behalf of certain securityholders of the Company (the “Selling Securityholders”).

The Securities were issued pursuant to a Letter Agreement, dated as of December 12, 2008 (the “Letter Agreement”), between the Company and the United States Department of the Treasury, which included the Securities Purchase Agreement – Standard Terms incorporated therein (the “Standard Terms”), the Annexes to the Standard Terms and the Schedules to the Letter Agreement (collectively, the “Securities Purchase Agreement”).

We are acting as counsel for the Company in connection with the registration for resale of the Securities. We have examined signed copies of the Registration Statement to be filed with the Commission, the Securities Purchase Agreement, the Warrant and such other documents as we have deemed necessary for purposes of rendering the opinions hereinafter set forth.

In our examination of the foregoing documents, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as copies, the authenticity of the originals of such latter documents and the legal competence of all signatories to such documents.

Our opinion below, insofar as it relates to the Preferred Shares to be sold by the Selling Securityholders being fully paid, is based solely on a certificate of an officer of the Company confirming the Company’s receipt of the consideration for such securities set forth in the Securities Purchase Agreement.

We assume that the appropriate action will be taken, prior to the offer and sale of the Securities, to register and qualify the Securities for sale under all applicable state securities or “blue sky” laws.

This opinion is limited solely to the Delaware General Corporation Law, as applied by courts located in Delaware, the applicable provisions of the Delaware Constitution and the reported judicial decisions interpreting those laws, and those laws, rules and regulations of the State of California that, in our experience, are normally applicable to transactions of the type contemplated by the Registration Statement, and we express no opinion as to the laws of any other jurisdiction.

Based upon and subject to the foregoing, we are of the opinion that:

1. The Preferred Shares to be sold by the Selling Securityholders have been duly authorized and are validly issued, fully paid and nonassessable.

2. The Warrant constitutes a valid and binding agreement of the Company, enforceable against the Company in accordance with its terms, except to the extent that enforcement thereof may be limited by (a) bankruptcy, insolvency, reorganization, fraudulent conveyance, moratorium or other similar laws now or hereafter in effect relating to creditors’ rights generally; and (b) general principles of equity (regardless of whether enforceability is considered in a proceeding at law or in equity).

3. The Warrant Shares have been duly authorized and, when issued upon exercise of the Warrant in accordance with the terms of the Warrant, the Warrant Shares to be sold by the Selling Securityholders will be validly issued, fully paid and nonassessable.

This opinion is to be used only in connection with the offer and sale of the Securities while the Registration Statement is in effect.

Please note that we are opining only as to the matters expressly set forth herein, and no opinion should be inferred as to any other matters. This opinion is based upon currently existing statutes, rules, regulations and judicial decisions, and we disclaim any obligation to advise you of any change in any of these sources of law or subsequent legal or factual developments which might affect any matters or opinions set forth herein.

We hereby consent to the filing of this opinion with the Commission as an exhibit to the Registration Statement in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act and to the use of our name therein and in the related prospectus under the caption “Legal Matters.” In giving such consent, we do not hereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission.

Very truly yours,

/s/ BINGHAM MCCUTCHEN LLP

Bingham McCutchen LLP