Mergers, rapid growth among Chinese law firms, and a healthy American market coalesced to turn 2018 into a spectacular year for the world's largest law firms.

Total revenue for the Global 100 increased a vigorous 8.1% over the past year, a step up from 2017's already robust 6.7% growth and a showing that dwarfs the 2.8% and 3.1% growth from the two preceding years. These firms brought in a collective $114.2 billion, more than the 2018 gross domestic product of Ecuador, the 60th largest economy in the world.

A total of 46 firms cracked the $1 billion mark, up from 34 firms two years ago. Of those 46 billion-dollar firms, all but nine have the bulk of their attorneys in the United States. Consequently, the American market continues to exert a heavy influence on the wider numbers. (The Am Law 100 posted 8% revenue growth in 2018.) Operating in an economy juiced by more than $1 trillion in tax cuts, the U.S. giants reaped the benefits.