DETROIT -

Gov. Rick Snyder has signed legislation overhauling Blue Cross Blue Shield of Michigan.

The bills let the state's largest health insurer transform into a customer-owned nonprofit and ends its tax-exempt status. The Republican governor signed the legislation Monday at a meeting of the company's board of directors in Detroit.

"This is going to allow them to be more successful. In terms of the old structures they were working under, it made them very difficult for them to be as efficient and effective as they can in the marketplace," Snyder said. "This legislation really creates an environment for Blue Cross to continue doing the great things and do them in a better environment instead of being constrained."

Supporters say the insurer must be modernized as it prepares for the federal health law and to participate in an online exchange where the uninsured can shop for insurance.

Critics say the bills are bad news for seniors because subsidies for their supplemental Medicare policies will eventually end. As part of the overhaul, Blue Cross will contribute nearly $1.6 billion over 18 years to an endowment working to improve public health and health care access.

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