In one of the largest executive-pay givebacks in history, former UnitedHealth Group Inc. Chief Executive William McGuire has agreed to forfeit about $620 million in stock-option gains and retirement pay to settle civil and federal-government claims related to stock-option backdating. The settlement comes a year after the options-backdating scandal led to Dr. McGuire's ouster from the Minnetonka, Minn., company, one of the largest U.S. health insurers. -snip- In the scandal, dozens of companies pretended that options were granted at an earlier date than they actually were. They picked dates when the stock price was at a low point, allowing executives...