PwC

PwC is the world’s largest professional-services firm, with $35.4 billion in revenue (which includes significant increases in the U.S., India, and China last year). The firm serves 418 of the companies on Fortune’s Global 500 list, advises more than 100,000 private businesses, and operates in 157 countries. It’s simply ubiquitous in everything from assurance (the $15.2-billion-in-sales unit that includes auditing) to tax ($8.9 billion) and advisory services ($11.3 billion). And if you don’t encounter PwC reps in your offices, you’ve probably seen them on the Academy Awards, for which the firm and its ancestors have been stewarding ballots for 82 years.