State officials say Illinois is on pace to end its fiscal year with about $1.2 billion in additional revenue.
The State Journal-Register reports most of the money is a one-time occurrence thanks to better-than-expected personal income tax collections and sales taxes.
Lawmakers constructed the budget based on a revenue estimate of $35.4 billion.
The figures were released by the Commission on Government Forecasting and Accountability, the General Assembly's fiscal forecasting arm.
Jim Muschinske is the commission's revenue manager. He says the solid performance of the stock market in 2013 helped boost the tax revenue, but warned that can't necessarily be expected to continue next year.
The state expects a significant revenue decrease next year because of an expected decrease in the income tax rate, which lawmakers are considering extending.
