The company is laying off 525 people nationwide.
According to a letter from Optum sent to the Employment Development Department, layoffs and departmental closures are being carried out in Los Angeles, San Bernardino, and Riverside counties.
Locations include Glendora, Montebello, Covina, Pasadena, Long Beach, Redlands, Highland, Los Angeles, Beaumont, Irvine, Hayward, El Segundo and Cerritos.
Optum didn't give a reason for the layoffs and didn't say if severance pay is being offered. The layoffs will take place in series of eight "waves," starting in September and ending in January.