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): May 22, 2014

INTERVEST BANCSHARES CORPORATION

(Exact Name of Registrant as Specified in Charter)

Registrant’s Telephone Number Including Area Code: (212) 218-2800

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:

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

(a) On May 22, 2014, the Board of Directors of Intervest Bancshares Corporation (the “Company”) approved the Annual Incentive Plan for Senior Executives (the “Plan”), which had been approved by the Compensation Committee and recommended to the Board of Directors. The Plan is included in this Report as Exhibit 10.1. The Plan is effective for the year ending December 31, 2014.

The participants in the Plan are the senior executive team of the Company, consisting of the following officers: the Chief Executive Officer (Lowell S. Dansker), the President of the Company’s bank subsidiary (Keith A. Olsen), the Chief Financial Officer (John J. Arvonio), the Vice President (Stephen A. Helman); and the Chief Credit Officer of the Company’s bank subsidiary (Robert Tonne).

Plan participants will be eligible to receive target incentive awards, calculated as a percentage of base salary. The annual target bonus for each officer is set out in the Plan. The Board, in its discretion, may make awards in the form of cash or shares of the Company’s common stock (which would be issued under the Company’s 2013 Equity Incentive Plan). In the case of the Chief Executive Officer and the President of the Bank, the components include loan originations, corporate goals and individual performance, with the specific allocations set out in the Plan. For the other participants, the components are corporate goals and individual performance. The incentive awards based on corporate results will be determined as the weighted-average percent of actual annualized results against pre-determined annualized goals in specified performance criteria related to: return on equity; percentage increase in net income; return on average assets; percentage of non-performing assets; and efficiency ratio, with the annual thresholds and goals as specified in the Plan. The individual bonus award is based on an evaluation of the individual’s performance in contributing to the success of the Bank, as determined by the Board of Directors in its discretion. No awards will be made under loan origination or annualized corporate goals unless the Company achieves a minimum 7.0% return on equity. Corporate-based awards will be a weighted-average percent of annualized goal attainment for the five areas mentioned above and annualized performance below the threshold level within any particular category will be considered zero. Calculated awards may be increased or decreased by up to 10% in the discretion of the Compensation Committee. The goals and thresholds have been established for 2014 and it is contemplated that they will be reviewed on an annual basis.

(b) On May 22, 2014, the Board of Directors of Intervest National Bank (the “Bank”) approved an increase in the base salary of Mr. Robert W. Tonne, Chief Credit Officer of the Bank, from $205,000 to $215,000. The salary increase is effective as of June 1, 2014.

The Annual Meeting of Shareholders (the “Meeting”) of the Company was held on May 22, 2014. As of the record date of March 31, 2014, there were a total of 22,021,190 shares of common stock outstanding and entitled to vote at the Meeting. At the Meeting, 20,547,174 shares of common stock were present in person or by proxy, representing a quorum.

At the meeting, the Company’s shareholders: (i) elected each of the ten persons listed below under “Election of Directors” to serve as a director of the Company until the next annual meeting of shareholders; (ii) approved a non-binding advisory proposal on executive officer compensation; and (iii) ratified the appointment of Hacker, Johnson & Smith, P.A., P.C., as the Company’s independent auditor for 2014.

The results of voting at the annual meeting on each such matter follows:

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.