A California bill that would eliminate health insurance companies and provide government-funded health coverage for everyone in the state would cost $400 billion and require significant tax increases, legislative analysts said Monday.

Much of the cost would be offset by existing state, federal and private spending on health coverage, the analysis found, but total healthcare costs would increase by an estimated $50 billion to $100 billion a year.

That’s a massive sum in a state where the entire general fund budget is $125 billion.

State Sen. Ricardo Lara, a Democrat, said he’ll propose a mechanism for raising the necessary tax revenue soon. The California Nurses Association, which is the driving force behind the bill, has commissioned a study to look at options.

The concept known as single-payer has energized liberals who are pushing Democratic lawmakers to approve the measure. The nursing union and other backers say eliminating…