Dreibach Accounting was New York based financial accounting corporation, which was mentioned in episode "The Shelf Life". It was Pearson Hardman's both client and accounting firm, as far as they signed a conflict of interest waiver. As described by Harvey "Drieback does the books for half of Wall Street".
Harvey and Mike found out that Dreibach Accounting carried out financial scam on Pearson Hardman through their so-called consultant firms, which were de facto only buyed shelf companies. One of them was Aberdeen Solutions, established for purpose of management services in June 2006, bought by them in 2010 and then dissolved.
Even through it was not explicitly shown in series, Dreibach Accounting most likely went bankrupt after Pearson Hardman sued Tory and their consultant firms.