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): July 25, 2013

Health Net, Inc.

(Exact Name of Registrant as Specified in Charter)

Registrant’s telephone number, including area code: (818) 676-6000

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:

On July 25, 2013, Health Net, Inc. (“we”, “us” or “our”) issued a press release announcing our financial results for the quarter ended June 30, 2013. The press release contains the non-GAAP financial measure “adjusted days claims payable (DCP).” Adjusted DCP for the second quarter of 2013 was 58.4 days, adjusted DCP for the first quarter of 2013 was 62.1 days, and adjusted DCP for the second quarter of 2012 was 54.3 days. Adjusted DCP excludes claims reserve and health plan costs related to our capitation, provider and other claim settlements and Medicare Advantage-Prescription Drug payables and costs. The most directly comparable GAAP financial measure to this non-GAAP financial measure is second quarter of 2013 DCP of 42.1 days, first quarter of 2013 DCP of 43.5 days and second quarter of 2012 DCP of 39.0 days.

Management believes that adjusted DCP provides useful information to investors because the adjusted DCP calculation excludes from both claims reserve and health plan costs amounts related to health care costs for which no or minimal reserves are maintained. Therefore, management believes that adjusted DCP may present a more accurate reflection of DCP than does GAAP DCP, which includes such amounts. This non-GAAP financial information should be considered in addition to, not as a substitute for, financial information prepared in accordance with GAAP. A reconciliation of the non-GAAP financial measure to the most directly comparable GAAP financial measure is included in the attached press release. As used herein, “GAAP” refers to accounting principles generally accepted in the United States.

The press release is attached hereto as Exhibit 99.1 and hereby incorporated in this Item 2.02 by reference. The information in this Item 2.02 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing by Health Net, Inc. under the Securities Act of 1933 or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Exhibit Index

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.