UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of report: May 3, 2016

(Date of earliest event reported)

Imperva, Inc.

(Exact Name of Registrant as Specified in Its Charter)

Delaware

(State or Other Jurisdiction of Incorporation)

(650) 345-9000

(Registrant’s Telephone Number, Including Area Code)

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:

On May 5, 2016, Imperva, Inc. (“Imperva” or the “Company”) issued a press release announcing its financial results for the first quarter ended March 31, 2016 and providing its business outlook. A copy of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K.

The information in this Item 2.02, including Exhibit 99.1 to this Current Report, is being furnished and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended. The information in this Item 2.02 and in the accompanying Exhibit 99.1 shall not be incorporated by reference into any registration statement or other document filed by Imperva with the Securities and Exchange Commission, whether made before or after the date of this Current Report, regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such filing.

Item 3.03 Material Modification to Rights of Securityholders.

The information contained in Item 5.03 of this Current Report is incorporated by reference into this Item 3.03.

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On May 3, 2016, the Compensation Committee of the Board of Directors of the Company approved an increase to the annual base salary of our Chief Technology Officer, Amichai Shulman, from approximately $210,000 to $245,000 and an increase to his annual target bonus amount from 30% of his annual base salary to 40% of annual base salary, effective immediately. Mr. Shulman resides in Israel and is paid in Israeli Shekels.

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

On May 4, 2016, the Board of Directors (the “Board”) approved an amendment and restatement of the Company’s Bylaws (the “Bylaws”), which became effective immediately upon their adoption by the Board. The material changes to the Company’s prior bylaws that were adopted on February 11, 2014 (the “Prior Bylaws”) include:

(1) Amending Section 1.4 (Stockholders – Adjournments) to allow the chairperson of a stockholder meeting to adjourn the meeting to another time, date and place, irrespective of whether a quorum is present.

(2) Amending Section 1.11(a) (Stockholders – Notice of Stockholder Business; Nominations – Annual Meeting of Stockholders) (the “Advance Notice Bylaw”), to add a requirement that in order for a stockholder to be eligible to propose a nomination or other business to be considered at an annual meeting of stockholders, such stockholder must have continuously beneficially owned at least 1% of the Company’s outstanding common stock for a period of one year before giving such notice (the “Stockholder Notice”).

(3) Amending the Advance Notice Bylaw to change the period during which a Stockholder’s Notice must be delivered to the Company for an annual meeting to 90 to 120 days before the anniversary of the last annual meeting, or in the case of a special meeting of stockholders, the later of the 90^th day before the special meeting and the 10^th day following the public announcement of such meeting and at the earliest, 120 days before the special meeting.

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(4) Amending the Advance Notice Bylaw to require that additional information be delivered to the Company in the Stockholder Notice, including:

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(5) Amending the Advance Notice Bylaw to add a requirement that to be eligible to be a nominee for director of the Company, any nominee proposed by a stockholder must:

(6) Amending the Advance Notice Bylaw to add a requirement that the stockholder giving the Stockholder Notice must actually appear in person or by proxy at the annual meeting to propose such business or nomination in order for such business or nomination to be properly considered. If such stockholder does not appear at the annual meeting, such proposed business or nomination may be disregarded or disallowed.

(7) Amending the Advance Notice Bylaw to add a definition of “Acting in Concert” that includes acting in conscious parallel with other parties.

The foregoing description of the material changes to the Prior Bylaws does not purport to be complete and is qualified in its entirety by reference to the text of the Bylaws, which are filed as Exhibit 3.1 hereto and incorporated herein by reference. In addition, a marked copy of the Bylaws showing all changes made to the Prior Bylaws is attached as Exhibit 3.2.

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Item 5.07. Submission of Matters to a Vote of Security Holders.

(a) The Company held its Annual Meeting of Stockholders on May 4, 2016 (the “Annual Meeting”). Proxies for the Annual Meeting were solicited pursuant to Regulation 14A of the Securities Exchange Act of 1934, as amended.

(b) The matters below, which are described in more detail in the Company’s proxy statement filed with the Securities and Exchange Commission on March 23, 2016, were voted on at the Annual Meeting and the number of votes cast with respect to each matter was as indicated.

(1) Holders of the Company’s common stock voted to elect two directors to serve on the Board as Class II directors, each to serve until the Company’s annual meeting of stockholders to be held in 2019 and until his or her successor is elected and qualified, or until his or her death, resignation or removal:

In addition, the following directors’ term of office continued after the Annual Meeting (and were not subject to a vote at the meeting): Charles Giancarlo, Albert Pimentel, Allan Tessler and James Tolonen. Messrs. Pimentel and Tolonen are Class III directors, whose term of office will expire at our annual meeting of stockholders to be held in 2017. Messrs. Giancarlo and Tessler are Class I directors, whose term of office will expire at our annual meeting of stockholders to be held in 2018. Theresia Gouw and Frank Slootman, whose terms expired at the Annual Meeting, did not stand for re-election.

(2) Holders of the Company’s common stock voted to approve the non-binding advisory resolution on compensation paid to the Company’s named executive officers, as disclosed pursuant to Item 402 of Regulation S-K, including compensation discussion and analysis, compensation tables and narrative discussion:

(3) Holders of the Company’s common stock voted to approve the amendment of the 2011 Stock Option and Incentive Plan to increase the number of shares available for grant under the plan by 1,300,000 shares and make certain other changes:

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(4) Holders of the Company’s common stock voted to ratify the appointment of Ernst & Young LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2016:

(d) Exhibits.

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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 thereunto duly authorized.

Date: May 5, 2016

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EXHIBIT INDEX