UnitedHealth, the US health insurer, on Wednesday slashed its earnings forecast for a second time this year, blaming “an intensely competitive commercial business environment”, as the company announced it had settled a class-action suit for more than $900m.

The company said it had settled the suit, brought by two different pension funds – Calpers, the California public employees pension fund; and the Alaska Plumbing and Pipefitting Industry Pension Trust. The suits concerned UnitedHealth’s stock options practices, and the settlements will cost the company $912m.