How much an HMO spends on overhead versus health care shows whether it is a responsible steward of insurance premiums. Industry leaders say spending 10 to 12 percent of revenues on administrative costs is ideal. But Minnesota Attorney General Mike Hatch alleges that Allina Health System uses nearly half of the premium dollars paid to its health plan, Medica, to support the administrative costs of five of its major businesses.

How Medica premium revenues are spent

Total: $1 billion

Hatch's estimate

Health care, taxes, other: 53 percent

Administrative: 47 percent

Allina's estimate

Health care, taxes, other: 88 percent

Administrative: 12 percent