Public company LIFO reserves fell from 2012 to 2015, a time when commodity prices generally fell, and LIFO reserves and commodity prices both rose moderately in 2016. Using a combination of Internal Revenue Service (IRS) and public company data, we estimate overall U.S. LIFO reserves from 2012 to 2016, and the potential tax revenue impact of LIFO repeal. At a 35 percent (20 percent) rate, taxing the 2016 LIFO reserves would yield between $19 ($11) and $24 ($14) billion. Although less than 1 percent of 2013 corporate and partnership tax returns with inventory used LIFO, LIFO inventories comprised about 14 percent of the dollar value of U.S. company inventories. The findings on LIFO usage and the magnitude of LIFO reserves are relevant to deciding whether LIFO should be retained as an acceptable inventory method for taxes and U.S. GAAP, and also provide context for instructors teaching about inventory methods.