UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 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 13, 2017

ZIX CORPORATION

(Exact name of registrant as specified in its charter)

2711 North Haskell Avenue

Suite 2200, LB 36

Dallas, Texas 75204-2960

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: (214) 370-2000

Not Applicable

(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:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Indicate by check mark whether the registrant is an emerging growth company as defined in 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 7.01 Regulation FD Disclosure

On September 13, 2017, Zix acquired Entrust Datacard’s Entelligence Messaging Server (EMS) technology and related business by way of an asset purchase (the “Acquisition”). The purchase price was $1.65 million and Zix will pay Entrust Datacard an additional $150,000 related to transition services.

On September 14, 2017, the Company issued a press release announcing the Acquisition. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K. In accordance with General Instruction B.2 of Form 8-K, the information set forth in this Item 7.01 and in the attached Exhibit 99.1 shall be deemed to be “furnished” and shall not be deemed to be “filed” for purposes of the Securities Exchange Act of 1934, as amended.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

SIGNATURES

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.

INDEX TO EXHIBITS