Health and Human Services Secretary Kathleen Sebelius announced that the insurer should extend a 'detailed justification' for its plan to raise premiums on individual policies by as much as 39%.

Earlier this month, Anthem Blue Cross of California issued out notices to nearly 800,000 holders of individual policies, informing them about the increase in the costs of their plans to cover rising health-care costs.

California insurance regulators have ordered Anthem Blue Cross to delay controversial rate increases of as much as 39% for individual policies, hikes that have landed subscribers and brokers in frenzy.

The Obama administration summoned California's largest for-profit insurer to pose a justification its rate lifts, revealing that the increases were alarming at a time when subscribers face soaring healthcare costs.

"With so many families already affected by rising costs, I was very disturbed to learn through media accounts that Anthem Blue Cross plans to raise premiums for its California customers by as much as 39%", Sebelius wrote to company President Leslie Margolin.

Poizner posted in his letter to WellPoint's chief executive and chairman that he would stand against the Anthem's rate hike and would end it if the actuary determines that the insurer spends less than 70% of its premiums on benefits, as required by state law.