What are the downsides of using an S Corporation?

First, please take a look at this FAQ. Once you understand why you may want to use a C Corporation, you’ll understand several of the reasons that an S Corporation may not work for you. Next, other downsides include not being able to have more than 100 shareholders, and not being able to have non-individual shareholders (generally), i.e., a corporation cannot be a shareholder of an S Corporation.