The latest revenue projections show Indiana could end the current fiscal year with a $1.8 billion surplus, an amount that would trigger an automatic refund to taxpayers under a new law.
The state could collect $516 million more than it expected when it crafted the current two-year budget based on last April's revenue projections.
That amount does not include an extra $288 million the state received after it detected a computer glitch that failed to transfer money to the general fund.
The surplus would total 12.2% of spending for the next budget year, exceeding the 10% threshold that triggers a taxpayer refund.
Legislators will debate what to do with the extra money during the upcoming session that begins Jan. 4.
The surplus comes from budget savings and higher-than-expected revenues during the 2010 fiscal year that ended in July, according to state officials.