Performing the Securities and Exchange Commission-mandated audit of a public company is one of the marquee services of public accounting firms -- it is, in fact, the one thing that they can do that no one else can.

And yet the vast majority of CPA firms will never conduct an SEC audit; the universe of firms providing this critical service is remarkably small compared to the universe of accounting firms as a whole. At the same time, the universe of public companies is also much smaller than you might think -- while small private businesses number in the millions, audit-seeking public companies number in the tens of thousands. These two facts together mean that competition for SEC clients is fierce, with each client gain or loss celebrated or lamented.

And so Accounting Today is happy to announce a new feature that will track those much-studied changes in the SEC marketplace, and report on them on both a quarterly and an annual basis. This scorecard is made possible through a partnership with Audit Analytics, which delivers audit, regulatory and disclosure intelligence, and is considered the best primary data source for benchmarking and analysis of auditor information, Sarbanes-Oxley disclosures, financial restatements, SEC comment letters, and corporate and legal actions.

"Audit Analytics is pleased to team up with Accounting Today to provide a quarterly and annual analysis of the wins and losses in the SEC audit market place," said Audit Analytics vice president of sales and marketing Joe Cyr. "Throughout the year we also plan to deliver market share analysis on the overall SEC audit market, as well as several other key audit markets, such as broker-dealers, registered investment advisors and private funds."

Our first installment focuses on the fourth quarter of 2012. Next month we'll bring you final results for 2012 as a whole. Finally, a quick word on how to read the top table: The firms listed down the lefthand side are those gaining or losing clients; the firms listed across the top are the ones they're gaining clients from, or losing them to.

To see the full chart, click here.