One of California’s top health insurers is calling for whopping rate hikes of up to 20 percent despite the fact it has a reserve fund of $3.9 billion.

And angry health care advocates say that Blue Shield of California should be using some of that huge sum to help reduce the proposed hikes, The Los Angeles Times reports.

"Blue Shield is sitting on a huge surplus that is beyond what is required or necessary," Laurie Sobel, a senior attorney for Consumers Union in San Francisco, told the newspaper.

"It should be used to hold down rate increases when it hits these extraordinary levels."

Blue Shield is seeking an average rate increase of 12 percent for more than 300,000 customers, with a maximum increase of 20 percent. The increases, if approved, would go into effect in March.

The insurance company said its substantial reserves have been stockpiled for the future benefit of policyholders.

"Reserves are needed to ensure our members' claims can be paid no matter what. We need them to protect against uncertainties like a pandemic or another crisis," Blue Shield spokeswoman Lindy Wagner told the Times.

California regulators are reviewing the proposed hikes and are expected to make a decision on them early next year.