People with health insurance saved $3.4 billion on their premiums last year as carriers led by UnitedHealth Group Inc. responded to U.S. limits on earnings and administrative costs, the government said. Rebates will lead to an additional $500 million in savings.

About 8.5 million Americans are expected to get rebates from their insurers averaging $100 because of rules that forbid plans from keeping more than 20 percent of premiums for profits and overhead.