Despite a record-breaking year for big-ticket M&A work, the most profitable New York-based firms saw much slower earnings and revenue growth on average in 2015. Those with heavy banking and private equity clienteles were whipsawed by the withering of litigation related to the financial crisis, a capital markets drought that began in July, and a longer wait for fees, according to several firm leaders.

Revenue growth for a benchmark group of 17 elite New York-based firms averaged 2.3 percent last year, down from 4.5 percent for the same firms in 2014. Profits per equity partner increased by an average of 2.6 percent, compared with 5.6 percent in 2014. None of the firms experienced double-digit increases in revenues, compared with three firms a year earlier. And two of them, Cadwalader, Wickersham & Taft and Cahill Gordon & Reindel, experienced a third straight year of declining profitability.