Simply, the capial gains tax is set to increase from 15% as of Dec 31, 2012 to about 20-25% in the next year. This will occurr if Congress does nothing and the Bush tax cuts expire. Popular belief however, is they will come up with a deal and extend at least some of the cuts for 1-2 years. By selling in 2012, ypou are locking in the capital gains rate of 15%. By waiting, you are gambling that the tax does not go up. There are other options on how to structure the sale that can result in postponing the tax due such as Sec 1031. These would need to be planned ahead of the sale and will need an intermediary to take possession of the sales proceeds in the interim between sales of your company and receipt of the stock of another. Hope this helps