After four straight years of profitable growth, Minnesota's health plans have stockpiled a substantial surplus of cash reserves. The health insurance companies, which get nearly three-quarters of their business from state and federal programs, now have more than $1.9 billion in reserves — $1.3 billion more than required by state law, according to a review by Twin Cities health care analyst Allan Baumgarten. "It's so much more than they would ever need, even if there was a flu outbreak," Baumgarten said. Combined, the HMOs have enough in reserves to cover 3.2 months of medical claims if no revenue were coming in, according to the analysis Baumgarten released Monday.