Buying or selling an interest in a closely held corporate business is an important transaction. CPAs must be prepared to fully consider the unique tax characteristics of an S corporation to advise their clients, whether sellers or buyers. We'll consider buyer and seller perspectives, relevant law, tax planning opportunities, pitfalls to avoid and necessary compliance issues. Review rules related to determining the stock basis of an S corporation, treatment of suspended losses, distributions, accumulated adjustment accounts, the built-in gain tax, excess net passive income tax, allocation of income and losses related to changes in ownership of an S Corp, and tax treatment of S corporation terminations. Finally, consider different tax consequences of asset and stock sales, including Sect. 338 and 336(e) elections.