I believe you are referring to the 5% credit on capital gain income in Utah. To qualify, the transaction must have occurred on or after January 1, 2008. At least 70% of the capital gain must have been reinvested in a qualified Utah small business within the year, and the taxpayer must not have a previous interest in the small business.
To calculate the credit, you multiply your capital gain by 4.95% and that is the amount of your credit.