Oklahoma makes official revenue estimates that determine how much the Legislature is allowed to appropriate in its annual budget for state agencies. The Legislature is limited to appropriating no more than 95 percent of certified collections. Revenue estimates are certified three times each year:
- In late December the State Board of Equalization makes a preliminary estimate. This estimate becomes the basis of the Governor’s budget proposal.
- In mid-February, the Board of Equalization makes a revised estimate considering changes in revenue collections and economic conditions. This establishes the maximum amount the Legislature can budget under existing laws for the coming year.
- In late June, the Board may revise the official revenue estimate up or down only if the Legislature has made changes to the law that affect state revenue.
Revenue estimates for Oklahoma’s major taxes are prepared by the Oklahoma Tax Commission based on a model developed by an economist at Oklahoma State University. Other taxes and fees are estimated by other means.