UnitedHealth Sued by Investor Over Antitrust Firewall, Probe (1)

UnitedHealth Group Inc. failed to avoid antitrust problems in its acquisition of Change Healthcare Inc. by adequately separating its business units, prompting a government investigation and a stock drop, an investor says in a proposed class action.

Before the public learned of the US Department of Justice probe in February, the company’s chairman sold more than $105 million worth of stock and its CEO sold more than $15 million worth, a Hollywood, Fla., pension fund says in the proposed class action, filed Tuesday in the US District Court for the District of Minnesota.

After the investigation was made public Feb. ...