The number of finance directors at the top 100 law firms who fear that M&A weakness will hit financial performance has risen to nearly a quarter - up 8% compared to 2015, according to research by Thomson Reuters Legal. Global M&A activity dropped 18% in the first quarter of this year compared to 2015, as firms grapple with a Brexit vote blow to business confidence, a slowdown in China, and the ongoing oil price slump. The UK has also experienced a slowdown in initial public offerings on the London Stock Exchange, slipping from 137 in 2014 to 92 last year, separate research from PwC revealed. Samantha Steer, Thomson Reuters UK&I Legal's director, large law segment, said: "The buoyancy in M&A transaction volumes last year was a key driver of profitability for law firms, but further growth was in question even before the Brexit vote and will be even more so now.