Shares in Molina Healthcare Inc. gained 3 percent Thursday after the Standard & Poor’s SmallCap 600 index said the health care provider will replace Keystone Automotive Industries Inc. on the index on Friday.

Keystone is being acquired by LKQ Corp. for about $800 million and will become a privately owned company. The acquisition was approved Wednesday by the Pomona-based auto parts supplier’s shareholders and is expected to close next week.

Shares in Long Beach-based Molina were up 2.5 percent to $35.51 Thursday in afternoon trading on the New York Stock Exchange. Shares in the health care provider are up 20 percent since February.