Emanuel said the increased competition through exchanges will hurt insurers' profits, so because of "uncertainty about next year, they're trying to lock in high rates" now.
Insurance companies maintain that premiums rise because of increases in the underlying cost of healthcare services.
Emanuel said premium hikes in some states do stem in part from rising medical costs for some groups. Premiums are rising for individual plans and small businesses faster than they're increasing for large employers, Emanuel noted.
The healthcare law does not give the Obama administration the power to reject large premium increases, although some states have that authority.