With record-breaking M&A volume pushing past the $5 trillion mark in 2015, it's no surprise that deal-hungry Am Law 100 firms wasted little time scooping up market share to start 2016.

As previously reported here, Skadden, Arps, Slate, Meagher & Flom had a record- breaking year, advising on more than $1 trillion worth of deals. Corporate Counsel, a sibling publication, noted earlier this week that Skadden's 20 percent market share took first prize for legal advisers, followed by Cravath, Swaine & Moore and Wachtell, Lipton, Rosen & Katz, respectively. The Financial Times also cited Dealogic data in its own story on the deal dominance of New York-based firms over their global brethren.

But other research shows that Magic Circle firms—the top of the London-based legal crop—fared better when using other metrics. U.K. publication Legal Week reported on Mergermarket data showing that Freshfields Bruckhaus Deringer and Linklaters snagged lead legal advisory roles on a third of Europe's blockbuster transactions in 2015.