UnitedHealth Groups' third-quarter earnings soared 26 percent to beat Wall Street expectations as its growing Optum business segment once again helped the nation's largest health insurer. The Minnetonka, Minnesota, company earned nearly $2.49 billion as revenue grew 9 percent to $50.32 billion. Adjusted earnings totaled $2.66 per share. FactSet says analysts had expected earnings of $2.56 per share on $50.35 billion in revenue. Health insurance is UnitedHealth's main business.