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The TABOR Amendment, which was approved by voters in 1992, limits the amount of revenue the State of Colorado can retain and spend.1  The TABOR limit “base” is equal to the lesser of the prior fiscal year’s revenue limit grown by Colorado inflation and population growth, or the current fiscal year's revenue.  Referendum C, which was approved by voters in 2005, allows the state to retain and spend an amount of revenue above the TABOR limit base.2  This amount is limited by the Referendum C “cap,” which grows by inflation plus population growth from FY 2007-08 revenue.  Surplus revenue in excess of the Referendum C cap must be refunded to Colorado taxpayers.  The money is refunded from the state’s general operating fund, known as the “General Fund.”

The TABOR Amendment requires voter approval for tax increases.  Fees, which are not addressed in this handbook, can be increased by the state legislature without voter approval.  Voter approval is also required to increase the TABOR limit, which constrains state revenue from both taxes and fees.

For more information about TABOR and Referendum C, visit the Legislative Council Staff website.  TABOR revenue reports can be found on the Office of the State Controller website.


1Colo. Const. art X, § 20.
2Section 24-77-103.6, C.R.S.
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