State concerns may stall WellPoint sale.

Opposition from California officials and the Calpers pension fund may succeed in at least delaying Anthem Inc.'s $16.4 billion purchase of Thousand Oaks-based WellPoint Health Networks Inc., according to investors who own shares in both companies.

The merger, announced in October, would create the largest U.S. health insurer. It was expected to close around midyear after a shareholder vote scheduled for June 28.

California is the only holdout among 11 states reviewing the purchase, and the California Public Employees' Retirement System has sought hearings on the more than $600 million WellPoint executives may receive.

State Treasurer Philip Angelides opposes the takeover and state Insurance Commissioner John Garamendi has said it may hurt patients. The companies may face concessions, investors said.

"It may mean some negotiation with California and figuring out something that satisfies everybody," said Michael Obuchowski, who manages $35 million at Altanes Investments LLC, including shares of WellPoint and Indianapolis-based Anthem.

The planned payout for WellPoint Chief Executive Leonard Schaeffer may be vulnerable in any negotiations between the companies and the state, said Steven Hill, a fund manager at First Investors Corp., which owns about 130,000 Anthem shares. He estimated Schaeffer's payouts at $76 million.

"I fully expect that WellPoint is going to do what needs to be done" to win clearance, said Hill, adding that California's objections will slow, but not stall, the acquisition.

The combined company would have 26 million members and cover about one in three members of Blue Cross plans nationwide.