The U.S. Securities and Exchange Commission has taken an interest in the executive compensation practices of a large health carrier.

The SEC has sent a formal order of investigation to UnitedHealth Group Inc., Minnetonka, Minn., UnitedHealth says in a report filed with the SEC.

The SEC sent UnitedHealth an informal inquiry about its stock option compensation practices in April, the company says.

“The company has cooperated and will continue to cooperate with the SEC,” UnitedHealth says.