Governor JB Pritzker has donated another $51.5 million of his own money to a committee working to make the "fair" tax happen.
The contribution to Vote Yes for Fairness, a committee headed by the governor's former deputy campaign manager, was reported late Friday in a filing with the State Board of Elections, according to the Associated Press.
The money is in addition to the $5 million donation the governor made last December.
Last year, the Illinois General Assembly approved legislation that will ask Illinois voters on the November ballot whether the state constitution should be amended to replace the current 4.95% flat rate on income tax with a graduated tax structure, in which people who earn more pay a greater percentage of their income.
But Republican lawmakers and pro-business groups contend that the legislation would create an opportunity for Democrats to adjust tax rates to cover the bills.
Illinois voters will decide if the graduated income tax plan will become law on November 3.
If voters approve the amendment, new tax rates approved last year by the General Assembly would go into effect Jan. 1. It would mean that the rates for individuals earning $250,000 or less would stay the same or go down and the rates of those who earn more than that would increase.
The Associated Press contributed to this article.