UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 4)*

BOSTON PRIVATE FINANCIAL HOLDINGS, INC.

(Name of Issuer)

Common Stock, par value $1.00 per share

(Title of Class of Securities)

101119105

(CUSIP Number)

Jeffrey Ferguson

The Carlyle Group

1001 Pennsylvania Avenue, NW

Suite 220 South

Washington, D.C. 20004-2505

(202) 729-5626

Copy to:

Maripat Alpuche, Esq.

Simpson Thacher & Bartlett LLP

425 Lexington Avenue

New York, New York 10017

(212) 455-2000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

February 28, 2012

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.  ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

This Amendment No. 4, dated February 29, 2012 (this “Amendment No. 4”), supplements and amends the Schedule 13D filed on September 3, 2008 (the “Original Schedule 13D”), as amended by Amendment No. 1 filed on October 9, 2008 (“Amendment No. 1”), Amendment No. 2 filed on June 23, 2010 (“Amendment No. 2”) and Amendment No. 3 filed on August 22, 2011 (“Amendment No. 3”), by BP Holdco, L.P. (“BP Holdco”), TCG Financial Services, L.P., Carlyle Financial Services, Ltd., TC Group Cayman Investment Holdings, L.P., TCG Holdings Cayman II, L.P., DBD Cayman, Ltd. and DBD Cayman Holdings, Ltd. with respect to the Common Stock of the Issuer. Capitalized terms used in this Amendment No. 4 and not otherwise defined herein shall have the same meanings ascribed to them in the Original Schedule 13D.

Item 4 of the Original Schedule 13D is hereby amended and supplemented by inserting the following text at the end thereof:

“On February 28, 2012, the Issuer repurchased for cash all of the Warrants held by BP Holdco and John Morton. The Issuer (i) repurchased Warrants held by BP Holdco, representing the right (subject to the exercise and other limitations therein) to purchase 5,383,891 shares of Common Stock, for $14,836,928.28, (ii) repurchased Warrants held by Mr. Morton, representing the right (subject to the exercise and other limitations therein) to purchase 59,174 shares of Common Stock, for $28,155.00 and (iii) made a cash payment of $134,916.72 to BP Holdco in respect of a cash payment that would have been payable to BP Holdco upon exercise of the Warrants held by Mr. Morton.”

The information set forth in Item 4 above is incorporated by reference in response to Item 6.

Item 7 is hereby amended by adding the following text to the end thereof:

“Exhibit 5 – Power of Attorney, dated February 11, 2011.”

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: February 29, 2012

Exhibit Index

Exhibit 5

POWER OF ATTORNEY

The undersigned understands that, from time to time, the Carlyle Companies (defined below) are required to prepare, execute and file certain federal and state securities laws filings.

Know all by these presents, that the undersigned hereby constitutes and appoints each of Curt Buser, Jeff Ferguson, David Pearson, Catherine Ziobro, R. Rainey Hoffman, Joanne Cosiol, Monica Harris, Jeremy Anderson, Bruno De Gusmao, Ann Siebecker, Andrea Pekala, Tom Mayrhofer, David Willich, Glen Goold, Orit Mizrachi, John Beczak, Rick Kappler, Matt LoRusso, Rob Konigsberg, Katey Bogue, James Sloan, or any of them signing singly, and with full power of substitution, the undersigned’s true and lawful attorney-in-fact to:

(1) prepare, execute in the name of each Carlyle Company and on behalf of each Carlyle Company, and submit to the U.S. Securities and Exchange Commission (the “SEC”) a Form ID, including amendments thereto, and any other documents necessary or appropriate to obtain codes and passwords enabling the undersigned to make electronic filings with the SEC of Forms D (“Form D”) required to be filed in accordance with Rule 503 (“Rule 503”) promulgated with respect to Sections 4(2), 4(6) and 3(b) of the Securities Act of 1933 (the “1933 Act”) and reports required by Sections 13(d) and 16(a) of the Securities Exchange Act of 1934 (the “1934 Act”) or any rule or regulation of the SEC;

(2) prepare and execute for and on behalf of each Carlyle Company, in the undersigned’s capacity as a Managing Director, authorized person, officer and/or director of each Carlyle Company, federal and state securities laws filings including without limitation Forms D pursuant to Rule 503 and Schedules 13D and 13G and Forms 3, 4, and 5 in accordance with Sections 13(d) and 16(a) of the 1934 Act and the rules thereunder;

(3) do and perform any and all acts for and on behalf of each Carlyle Company which may be necessary or desirable to complete and execute any such federal and state securities laws filings including without limitation Forms D, Schedules 13D and 13G and Forms 3, 4, and 5, complete and execute any amendment or amendments thereto, and timely file such form with the SEC and the securities administrators of any state, the District of Columbia, the Commonwealth of Puerto Rico, Guam and the United States Virgin Islands or their designees and any stock exchange or similar authority; and

(4) take any other action of any type whatsoever in connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in such attorney-in-fact’s discretion.

The undersigned hereby grants to each such attorney-in-fact full power and authority to do and perform any and every act and thing whatsoever requisite, necessary, or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as the undersigned might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that such attorney-in-fact, or such attorney-in-fact’s substitute or substitutes, shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted, whether the same needs to be executed, taken or done by him in his capacity as a current or former member, partner, shareholder, director or officer of any company, partnership, corporation, organization, firm, branch or other entity connected with, related to or affiliated with any of the entities constituting the Carlyle Companies or entities that directly or indirectly hold interests in the Carlyle Companies.

The undersigned acknowledges that the foregoing attorneys-in-fact, in serving in such capacity at the request of the undersigned, are not assuming any of the undersigned’s responsibilities to comply with federal and state securities laws, including without limitation Rule 503 of the 1933 Act or Section 13 and Section 16 of the 1934 Act.

This Power of Attorney and all authority conferred hereby shall not be terminated by operation of law, whether by the death or incapacity of the undersigned or by occurrence of any other event. Actions taken by an attorney-in-fact pursuant to this Power of Attorney shall be as valid as if any event described in the preceding sentence had not occurred, whether or not the attorney-in-fact shall have received notice of such event. Notwithstanding the foregoing, (i) in the event that an attorney-in-fact is no longer employed by The Carlyle Group Employee Co., L.L.C. or its affiliates, this Power of Attorney and all authority conferred hereby shall be immediately terminated with respect to such Attorney, and (ii) the undersigned may terminate or revoke this Power of Attorney at any time.

For purposes hereof, the “Carlyle Companies” shall consist of: (i) TWC Virginia, Inc., a Delaware corporation, TC Group, L.L.C., a Delaware limited liability company, TC Group Cayman, L.P., a Cayman Islands exempted limited partnership, TC Group Investment Holdings, L.P., a Delaware limited partnership and TC Group Cayman Investment Holdings, L.P., a Cayman Islands exempted limited partnership; (ii) their respective owners, including without limitation TCG Holdings, L.L.C., a Delaware limited liability company, TCG Holdings Cayman, L.P., a Cayman Islands exempted limited partnership, TCG Holdings II, L.P., a Delaware limited partnership, TCG Holdings Cayman II, L.P., a Cayman Islands exempted limited partnership, TCG Employee Co., L.L.C., a Delaware limited liability company, Carlyle Offshore Partners II, Ltd., a Cayman Islands exempted company with limited liability, Carlyle Offshore Partners II Holdings, Ltd., a Cayman Islands exempted company with limited liability, DBD Investors V, L.L.C., a Delaware limited liability company, DBD Investors V Holdings, L.L.C., a Delaware limited liability company, DBD Cayman, Ltd., a Cayman Islands exempted company with limited liability and DBD Cayman Holdings, Ltd., a Cayman Islands exempted company with limited liability; and (iii) the subsidiaries and affiliates of the foregoing in clauses (i) and (ii), including without limitation investment funds sponsored directly or indirectly by one or more of the Carlyle Companies.

[Signature Page Follows]

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of this 11^th day of February, 2011.

On the 11th day of February, 2011, before me personally came and appeared David M. Rubenstein to me known and known to me to be the individual described in and who executed the foregoing instrument and who duly acknowledged to me that he executed the same.

My term expires: February 28, 2014