This paper uses data from the Survey of Consumer Finances (SCF) and the NBER TAXSIM model to estimate marginal and average tax rates for households that own businesses that are pass-thru entities. We examine how marginal and average tax rates vary by the size of business using four different measures of the size: net income, gross receipts, business value, and number of employees. The analysis also uses the long-time series of SCF cross-sections to examine how tax rates for business owners have evolved over the various changes in tax policy of the last two decades.