With more than $100 million spent by both sides, the battle over the graduated income tax amendment has become the most expensive ballot initiative in Illinois history. Around $110 million has been spent by both sides on the amendment.
Income tax amendment most expensive ballot initiative in Illinois history. See story here. https://abc7chicago.com/politics/il-graduated-income-tax-amendment-most-expensive-ballot-initiative-in-state-history/7590817/