Managed care company UnitedHealth Group Inc.'s Optum business plans to buy the operations of Southern California physician group Monarch HealthCare. Terms of the deal were not disclosed Thursday by Optum, which provides health management, consulting and pharmacy services. UnitedHealth, based in Minnetonka, MN, is the largest health insurer based on revenue and second only to WellPoint Inc. in enrollment. Monarch, founded in 1994, has more than 2,300 doctors who provide care for about 200,000 residents of California's Orange County. Optum CEO Larry Renfro said in a statement that Optum shares Monarch's "commitment to bringing patients, physicians, hospitals and health care payers closer together in the mission to increase the quality and affordability of care." Analysts say insurers are showing a growing interest in expanding into other elements of health care delivery. Jefferies analyst Arthur I. Henderson said in a research note he expects insurers to move more proactively into employment-like deals with care providers to lower costs by improving care coordination.