Illinois Gov. Pat Quinn is defending a massive increase in state income taxes and promises to sign the bill passed by lawmakers quickly.

Lawmakers worked overnight Wednesday to pass the increase to raise the personal income tax rate from 3 percent to 5 percent for four years. Corporate income taxes also will rise, and Quinn rejected the notion that it would decimate businesses.

Quinn says the tax increase money will help heal the state’s ailing finances. Illinois is facing a deficit that could top $15 billion this year.

The Chicago Democrat says it’s important for the Illinois economy that state government not be a “fiscal basket case.”

The rate increase might be the biggest any state has adopted in percentage terms while grappling with recent economic woes.