(1) As used in this section, the term:(a) “Net collections” for a fiscal year means the total amount of taxes collected under this chapter by the department in a state fiscal year, including related interest and penalties, minus the total amount of refunds of taxes levied under this chapter and issued by the department in that fiscal year. No later than September 1 of each year, the Office of Economic and Demographic Research shall determine net collections for the most recent fiscal year.
(b) “Forecasted net collections” for a fiscal year means the amount of net collections forecasted for a fiscal year by the Revenue Estimating Conference on February 23, 2018.
(c) “Adjusted forecasted collections” for a fiscal year means forecasted net collections for a fiscal year multiplied by 1.07.
(d) “Tax rate imposed” is the tax rate as defined in ss. 220.11(2) and 220.63(2) adjusted as set forth in this section. (2) The tax rate imposed shall be adjusted based on net collections in each of the fiscal years 2018-2019 through 2020-2021. If the net collections for a fiscal year exceed the adjusted forecasted collections for the same fiscal year, the tax rate imposed for taxable years beginning on or after January 1 of the calendar year in which the fiscal year ends shall be the tax rate imposed for taxable years beginning on or after January 1 of the preceding calendar year multiplied by the quotient of the adjusted forecasted collections for the fiscal year divided by the net collections for the same fiscal year. The resulting tax rate shall be rounded to the nearest thousandth and rounded down if the fourth digit to the right of the decimal point is the number five. The resulting tax rate shall be the tax rate imposed for subsequent taxable years for purposes of ss. 220.11(2) and 220.63(2) unless adjusted further under this section. (3) By October 1, 2019, October 1, 2020, and October 1, 2021, the Department of Revenue shall calculate the tax rate imposed, if it is to be adjusted pursuant to subsection (2), and shall on that same date report the results of such calculation to the Governor, the President of the Senate, and the Speaker of the House of Representatives.
(4) For fiscal years 2018-2019 through 2020-2021, any amount by which net collections for a fiscal year exceed adjusted forecasted collections for that fiscal year shall only be used to provide refunds to corporate income tax payers as follows:(a) For purposes of this subsection, the term:1. “Eligible taxpayer” means:a. For fiscal year 2018-2019, a taxpayer whose taxable year begins between April 1, 2017, and March 31, 2018, and whose final tax liability for such taxable year is greater than zero;
b. For fiscal year 2019-2020, a taxpayer whose taxable year begins between April 1, 2018, and March 31, 2019, and whose final tax liability for such taxable year is greater than zero; or
c. For fiscal year 2020-2021, a taxpayer whose taxable year begins between April 1, 2019, and March 31, 2020, and whose final tax liability for such taxable year is greater than zero.
2. “Excess collections” for a fiscal year means the amount by which net collections for a fiscal year exceeds adjusted forecasted collections for that fiscal year.
3. “Final tax liability” means the taxpayer’s amount of tax due under this chapter for a taxable year, reported on a return filed with the department, plus the amount of any credit taken on such return under s. 220.1875. 4. “Total eligible tax liability” for a fiscal year means the sum of final tax liabilities of all eligible taxpayers for a fiscal year as such liabilities are shown on the latest return filed with the department as of February 1 immediately following that fiscal year.
5. “Taxpayer refund share” for a fiscal year means an eligible taxpayer’s final tax liability as a percentage of the total eligible tax liability for that fiscal year.
6. “Taxpayer refund” for a fiscal year means the taxpayer refund share for a fiscal year multiplied by the excess collections for a fiscal year.
(b) No later than April 15 following a fiscal year, the department shall determine total eligible tax liability for that fiscal year, the taxpayer refund share for that fiscal year for each eligible taxpayer, and the taxpayer refund for that fiscal year for each eligible taxpayer.
(c) No later than May 1 following a fiscal year, the department shall refund a taxpayer refund for that fiscal year to each eligible taxpayer.
(5) For taxable years beginning on or after January 1, 2022, the tax rate adjustments pursuant to this section are repealed and the tax rate imposed for purposes of s. 220.11(2) and 220.63(2) is 5.5 percent. 
