The pharmaceutical industry saw major consolidation in 2009 through large mergers and acquisitions that reshuffled the rankings of the top pharma companies. Pfizer emerged as the clear number one company after acquiring Wyeth. Merck's merger with Schering-Plough will likely make it the number four company in 2010. Growth through M&A is expected to continue as companies seek new drugs and markets, and the largest pharma companies are approaching $40 billion in annual revenue. Emerging markets are becoming increasingly important as their drug spending catches up to traditional markets.