Let’s say in 2011, your accountant suggested it might be good to elect S Corporation treatment for your business which has been a C corporation for 5 years. You’ve got the hottest bar in town. Its worth $1 Million and you only invested $100,000 which is fully depreciated, but there are good years and bad years and you like the fact that you can deduct losses and avoid double taxation of income by using S. Fast forward to 2015. Porky comes by and wants to buy your name, assets. He’s offering $1.2 Million. You are so excited. Selling these assets would yield a gain at capital gains rates what could be better. Then you talk to your tax lawyer. He says wait. Under Section 1374 of the Internal Revenue Code there is a built in gains tax that looks back 10 years. Thus, if at the time of your S Election in 2011, your business was worth $1 Million, it must recognize that $1 Million at ordinary corporate rates. Thus, instead of the tax being $250,000 on the gain it is $565,000 give or take. A huge difference.