If there's one state health insurance companies don't want to lose, it's California.

So while industry observers have said they expect federal regulators to approve two potential health insurance megamergers, the strong objection levied against Indianapolis-based Anthem Inc.'s proposed $54 billion acquisition of Connecticut-based Cigna by the California insurance commissioner has to have executives and shareholders of the two companies worried.

Commissioner Dave Jones urged the federal government to block the deal, pointing to the enormous share of the Golden State's insurance market that the two companies control. If the two merge, he pointed out, the newly formed company would be particularly dominant in the self-insured market, accounting for 61 percent of self-insured employers in the state.