Doeren Mayhew Remains 14th-Largest Houston Accounting Firm 16 February 2016 Share Doeren Mayhew, a Houston CPA and advisory firm, has held its ranking in the 14th spot on the Houston Business Journal’s annual list of largest local accounting firms. Rankings for the 2016 list were based on the number of Houston CPAs, with Doeren Mayhew listing 34 CPAs and 82 employees locally. Read more.