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Definitive Proxy Statement

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Definitive Additional Materials

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Important Notice Regarding the Availability of Proxy Materials for the

Shareholder Meeting to Be Held on May 11, 2015

Meeting Type: Annual Meeting

For holders as of: March 09, 2015

Date: May 11, 2015         Time: 10:30 AM PDT

John J. Stewart

Four Embarcadero Center

Suite 3200

San Francisco, CA 94111

Location:    Four Embarcadero Center

Third Floor, Promenade Level

Conference Center

(Stanford Room)

San Francisco, CA 94111

You are receiving this communication because you hold shares in the above named company.

This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. You may view the proxy materials online at www.proxyvote.com or easily request a paper copy (see reverse side).

We encourage you to access and review all of the important information contained in the proxy materials before voting.

See the reverse side of this notice to obtain proxy materials and voting instructions.

Proxy Materials Available to VIEW or RECEIVE:

1. Form 10-K    2. Notice & Proxy Statement

How to View Online:

Have the information that is printed in the box marked by the arrow (located on the following page) and visit: www.proxyvote.com.

How to Request and Receive a PAPER or E-MAIL Copy:

If you want to receive a paper or e-mail copy of these documents, you must request one. There is NO charge for requesting a copy. Please choose one of the following methods to make your request:

1) BY INTERNET:         www.proxyvote.com

2) BY TELEPHONE:     1-800-579-1639

3) BY E-MAIL*:              sendmaterial@proxyvote.com

* If requesting materials by e-mail, please send a blank e-mail with the information that is printed in the box marked by the arrow (located on the following page) in the subject line.

Requests, instructions and other inquiries sent to this e-mail address will NOT be forwarded to your investment advisor. Please make the request as instructed above on or before April 27, 2015 to facilitate timely delivery.

Vote In Person: Many shareholder meetings have attendance requirements including, but not limited to, the possession of an attendance ticket issued by the entity holding the meeting. Please check the meeting materials for any special requirements for meeting attendance. At the meeting, you will need to request a ballot to vote these shares.

Vote By Internet: To vote now by Internet, go to www.proxyvote.com. Have the information that is printed in the box marked by the arrow available and follow the instructions.

Vote By Mail: You can vote by mail by requesting a paper copy of the materials, which will include a proxy card.

The Board of Directors recommends you

vote FOR the following:

1.    Election of Directors

        Nominees

1A    Dennis E. Singleton

1B    Laurence A. Chapman

1C    Kathleen Earley

1D    Kevin J. Kennedy

1E    William G. LaPerch

1F    A. William Stein

1G    Robert H. Zerbst

The Board of Directors recommends you

vote FOR proposals 2., 3. and 4.:

2.    To ratify the selection of KPMG LLP as

        the Company’s independent registered

        public accounting firm for the year

        ending December 31, 2015.

3.    To approve the Digital Realty Trust,

        Inc. 2015 Employee Stock Purchase Plan.

4.    To adopt a resolution to approve, on a

        non-binding, advisory basis, the

        compensation of the Company’s named

        executive officers, as more fully

        described in the accompanying Proxy

        Statement.

NOTE: TO VOTE AND OTHERWISE REPRESENT THE

UNDERSIGNED ON SUCH OTHER BUSINESS AS MAY

PROPERLY COME BEFORE THE ANNUAL MEETING OR

ANY ADJOURNMENT(S) OR POSTPONEMENT(S)

THEREOF IN THE DISCRETION OF THE PROXY

HOLDER.