ObamaCare plans cheaper than expected in key rate filing

The Congressional Budget Office predicted in 2009 that premiums for a middle-of-the-road exchange plan would come to about $5,200 per year. 

Other states have seen their rates track relatively close to that figure, but California's plans came in substantially lower — about $3,600 per year before subsidies.

Some young people in the state might not have to pay a premium at all — federal subsidies will be enough to cover the entire cost of one of the cheapest policies available. 

A 21-year-old who isn't eligible for a subsidy would pay $172 per month for the same policy.

Specific costs will vary throughout the state, and premiums also vary based on age and a handful of other factors. 

Most states' exchanges will accept any plan that meets federal standards. But California's exchange was established as an "active purchaser," meaning it can bargain directly with insurers for lower prices or richer coverage. 

That power helped the state achieve the low premiums released Thursday.

The exchange said more than 30 plans expressed interest in selling their policies through the exchange, but only 13 were ultimately accepted.