Federal regulators are suing to block UnitedHealth Group’s purchase of technology company Change Healthcare, a deal they fear will put too much health care claims information in the hands of one company. The U.S. Department of Justice said Thursday that the proposed deal would hurt competition and give UnitedHealth Group—which runs the nation’s largest insurer—access to sensitive claims information from competitors. “If America’s largest health insurer is permitted to acquire a major rival for critical health care claims technologies, it will undermine competition for health insurance and stifle innovation in the employer health insurance markets,” U.S. Attorney General Merrick Garland said in a statement. Justice Department officials said in the statement that the deal would give UnitedHealth control of a “critical data highway through which about half of all Americans’ health insurance claims pass each year.” They added that the company could then use that sensitive information from rivals for …