Public Company Accounting Oversight Board - PCAOB

Public companies undergo a rigorous accounting process to make sure that the numbers they report to their investors are truthful and accurate. Well, the process is supposed to be rigorous. Firms can game the system if they try hard enough.
You don't leave a two-year-old alone with a bag of cookies, and you don't leave a puppy alone with your grandma's hand-crafted heirloom afghan. Similarly, you don't leave corporate executives alone with a company's books. You need some oversight: both government regulators and industry organizations who will keep everyone honest.

The Public Company Accounting Oversight Board represents one of these groups. While it's technically a non-profit organization (and not a government regulator), the PCAOB was created by the Sarbanes–Oxley Act of 2002. The legislation passed after a series of corporate accounting scandals suggested that maybe, just maybe, the accounting at public companies could use a little more oversight. The two largest bankruptcies in American history (WorldCom and Enron) had just taken place, both precipitated by sketchy accounting practices.

So Congress created the PCAOB. Its purpose was to watch over the audits of public company finances, making sure the numbers were on the up and up.