April 8 (Bloomberg) — UnitedHealth Group Inc. and Humana Inc. are among the carriers that will see their base government payment rate reduced 4 percent next year for Medicare Advantage programs for elderly Americans.

While the base payment rate cut is more than the government's proposed 3.55 percent reduction in February, the Centers for Medicare and Medicaid Services said yesterday in a letter to insurers that it's delaying a proposal that would have lowered payments further. The agency put off a limitation on home assessments that industry analysts said would have meant an additional 2 percent cut for insurers.

About 15.9 million people, or 30 percent of Medicare beneficiaries, chose Advantage plans this year over the regular government-run program for the elderly and disabled, according to data from the government. Insurers have mounted a lobbying campaign to deter the cuts, enlisting letters from Republican and Democratic lawmakers and generating 56,000 phone calls from seniors, according to the industry's Washington lobbying group America's Health Insurance Plans, which called it their "largest-ever mobilization."