BDO knows accounting. BDO Seidman is the US arm of BDO International, one of the largest accounting firms outside of the Big Four (Deloitte Touche Tohmatsu, Ernst & Young, KPMG, and PricewaterhouseCoopers). The firm, which has more than 35 locations, offers midsized companies a broad range of accounting, consulting, and related services, including auditing, tax planning, strategic financial advising, litigation consulting, and appraisals and valuations. More than 400 additional offices are operated by independent US firms that are members of the BDO Seidman Alliance. The international BDO network includes more than 625 member firms around the globe. BDO Seidman was founded in 1910.