A new estimate puts the eventual cost of a Missouri tax cut proposal at more than $620 million annually.
Gov. Jay Nixon cited the projection Monday while asserting that the Senate legislation would "permanently undermine Missouri's ability to support K-12 and higher education."
Sponsoring Sen. Will Kraus had previously estimated the tax cut would waive less than $500 million of revenues annually, once fully implemented.
The bill would phase in a half-a-percentage-point reduction in Missouri's top individual income tax rate and a new 25 percent deduction for business income reported on individual tax returns. The tax cuts could start in 2017.
The bill also would expand the deductions available for lower income individuals and require the tax brackets to be adjusted annually for inflation.