The U.S. ethanol industry is lobbying hard for an extension of existing ethanol import tariffs and blenders tax credits before they expire at the end of 2010. The purpose of this study is to examine the likely consequences on the U.S. ethanol industry, corn producers, taxpayers, fuel blenders, and fuel consumers if current policy is not extended. Impacts of different ethanol policies in both 2011 and 2014 were estimated. Estimates were obtained by developing a new stochastic model that calculates market-clearing prices for U.S. ethanol, Brazilian ethanol, and U.S. corn. The model is stochastic because market-clearing prices are calculated for 5,000 random draws of corn yields and wholesale gasoline prices. Key assumptions in this study are that the strong growth in flex-fuel vehicles in Brazil continues; intermediate ethanol blends with few restrictions are implemented in U.S. markets in 2014; U.S. ethanol production capacity reaches 15 billion gallons in 2014; and Brazilian ethanol production increases by at least 45% by 2014. Projected strong demand for ethanol in Brazil combined with a largely saturated U.S. ethanol market means that elimination of ethanol import tariffs would have almost no impact on U.S. corn and ethanol markets in 2011. Elimination of the tax credit would impact markets modestly, with ethanol production declining by an average of about 700 million gallons. This reduction in ethanol production would cause corn prices to drop by an average of 23 cents per bushel. Ethanol prices would drop by 12 cents per gallon. Elimination of the tax credit would shift the burden of meeting mandates from taxpayers to blenders and consumers. Taxpayers would save more than $6 billion through elimination of the tax credit, or almost $7.00 per gallon of ethanol produced in excess of mandated amounts. The impacts of a change in U.S. ethanol policy in 2014 are larger than 2011 impacts because Brazil has a chance to respond by ramping up its ability to export in response to trade liberalization. But because of strong domestic demand growth in Brazil and limits on how fast Brazilian ethanol production can increase, the impacts of a change in policy are still modest. As long as the mandate is maintained, U.S. ethanol production drops by no more than 500 million gallons, corn prices drop by no more than 16 cents per bushel, and ethanol prices drop by no more than 35 cents per gallon. If the impact of intermediate blends is not as strong as assumed in this study, then there will be less incentive for Brazil to export ethanol and the impacts of tariff elimination would be even more modest.