Sharp divergence between pay at the most successful companies and also-rans in the same field
Bloom believes inequality is being magnified by technological change and what's known as skills bias, where workers with a particular expertise reap the biggest reward. Neither is amenable to quick fixes.
In Professor Bloom's new paper, which he wrote with David J. Price, a Stanford graduate student, and three other economists -- Jae Song, Fatih Guvenen and Till von Wachter -- the top quarter of 1 percent of Americans appears to be pulling away from the rest.
For workers at this threshold, who earn at least $640,000 annually, their salaries rose 96 percent from 1981 to 2013, after taking account of inflation.
The trend was especially pronounced among the most successful enterprises in the American economy, creating a divergence between the highest-paid people at companies that employ more than 10,000 people and the rest of the work force. In this rarefied circle, overall pay jumped 140 percent versus a 5 percent drop for the typical employee at these corporate behemoths.
The split in compensation between executives and everyone else was much less pronounced at smaller companies, according to the research by Mr. Bloom and his colleagues. At these firms, between 1981 and 2013, top salaries rose 49 percent, while median pay rose 30 percent.
In addition, Mr. Bloom and his team also found a sharp divergence between pay at the most successful companies and also-rans in the same field -- think Apple versus BlackBerry. The highest-paid workers cluster at the winners, heightening income disparities in the overall work force.
Mr. Bloom traces the outsize gains to large grants of stock and options to top workers at big companies, with their fortunes rising in line with the performance of the stock market.
"There used to be a premium for working at a big company, even in a lower-level job," he said. "That's not true anymore. The people who have really suffered are lower-level employees at big companies."