UnitedHealth Group Inc.'s former CEO William W. McGuire agreed on Thursday to repay over $400 million in compensation -- in addition to $200 million he previously gave up -- as part of a settlement deal with the company and government regulators over an options backdating scandal.

The massive settlement comes a year after the controversy led to McGuire's ouster from the company. He previously had been one of the most successful and highest-paid executives in the U.S.

``The last 18 months have been extraordinarily challenging period for my family and me,'' McGuire said in a statement.

``I am very pleased to have reached a resolution that puts these matters to rest, he concluded.

The Minnetonka, Minn.-based health insurer will seek to dismiss all lawsuits related to the matter, it said in a statement.

United Health reached a settlement deal with McGuire after a committee of two former Minnesota Supreme Court judges reviewed claims over UnitedHealth's stock option practices that were brought against a number of current and former officers and directors. United Health made no findings of wrongdoing by McGuire, it said in a statement.

McGuire agreed to return over $320 million in stock options. He will also return his interest in the company's supplemental executive retirement plan, worth nearly $92 million, and forfeit around $8 million in his executive savings plan account.

As part of a related, but separate settlement today with the U.S. Securities and Exchange Commission, McGuire agreed to pay the commission a civil penalty of $7 million and not serve as an officer or director of a public company for ten years.