Editor’s Note from The Legal Intelligencer: This is the first of a two-part series reviewing 2009 financial performance and the prospects for 2010. The first part examines revenue trends and the second will look at partner profits.

Three of the four largest Pennsylvania-based firms — Dechert, Morgan Lewis & Bockius and Reed Smith — lost a combined $192 million in revenue in 2009 thanks to a drop-off in demand of some of their core practice areas.