A House bill that won committee approval Monday would impose a tax on online sales, but it’s unknown how much revenue it would bring in or lose.

The bill, HB 1957, would introduce a tax on online sales from out-of-state retailers while adjusting income tax rates annually. The House Ways and Means Committee passed the bill Monday. It now goes to the full House.

The bill, known as the Wayfair legislation, gets its nickname from Wayfair Inc., which doesn’t pay sales tax since it doesn’t have brick-and-mortar facilities in Missouri.

The bill would adjust the top income tax rate annually, with the rate going up when sales tax fails to increase by a certain percentage in the previous fiscal year, and vice versa.

The adjustments are intended to make the bill revenue-neutral, but no one could say exactly how much will be gained or lost. The bill was backed by numbers that some members of the committee had never seen before the meeting.

The bill’s sponsor, Rep. J. Eggleston, R-Maysville, said the bill is “as close to break-even” as it will get. When asked about the exact numbers, he said he wasn’t sure.

The offices of two other committee members did not have copies of the fiscal note Monday afternoon. A fiscal note outlines projections for impacts on revenue.

Eggleston’s bill also eschews recommendations from Gov. Mike Parson. In Parson’s budget proposal, revenue raised by the Wayfair tax would have been directed to the cash-operating expense fund, which was envisioned as a rainy day fund for the state. Eggleston’s bill would direct taxes collected under the provision to general revenue.