Any money not spent by Missouri in a fiscal year would become a tax credit for the state's taxpayers under a measure heard by a Senate panel.
Republican Sen. Kurt Schaefer, of Columbia, told the Senate Ways and Means Committee on Thursday that his bill would give lawmakers an incentive not to overspend on government services.
Opponents argued it would give the governor and the Legislature the incentive to spend more than the state has to avoid a refund.
The measure would need to be approved by voters.
Missouri already has a constitutional provision, known as the Hancock Amendment, which triggers a tax refund after state revenues hit a certain cap. Missouri's actual revenues are well short of that amendment's cap.