Blue Shield of California has shocked its policyholders with a proposal to raise premiums by as much as 59 percent, effective March 1. The San Francisco-based company says the higher rates are needed to cover fast-rising costs. It's the second time in less than a year that a California health insurer has asked for a whopping increase. Last year, Anthem Blue Cross drew sharp criticism from the Obama administration after requesting a 39 percent rate hike. Anthem Blue Cross ultimately settled for a 20-percent hike.