A large managed care company says it has finished correcting the way it accounted for stock-based compensation expenses.

UnitedHealth Group Inc., Minnetonka, Minn., estimates the corrections have reduced net income about $57 million from the reported total for 2005 and about $502 million for the 12-year period that ended Dec. 31, 2006.

The accounting errors also reduced shareholders’ equity about $130 million, and making the corrections will require the company to pay about $100 million in extra federal income taxes, UnitedHealth estimates.

UnitedHealth also will record a $90 million charge, before taxes, to cover the cost of settling Internal Revenue Code Section 409A surtax liabilities for non-officer employees who exercised some options in 2006, the company says.