A trio of Am Law 100 firms ended 2013 outpacing their rivals in three separate rankings of M&A legal advisers thanks largely to their work on a few of the year’s largest transactions—including one that ranks as the third-largest M&A deal in history.

Davis Polk & Wardwell, Simpson Thacher & Bartlett and Wachtell, Lipton, Rosen & Katz ranked as the top three firms, in varying order, in each of the so-called league tables released at the end of the year by Bloomberg, Mergermarket and Thomson Reuters. The three outlets rank legal advisers based on the total value of their corporate clients’ global M&A transactions over the course of 2013. Mergermarket and Thomson Reuters both ranked Davis Polk first, followed by Wachtell and Simpson Thacher, respectively. Simpson Thacher topped Bloomberg’s ranking, followed by Davis Polk and Wachtell, respectively.

Davis Polk leaped to the lead from 14th place in the 2012 Mergermarket and Thomson Reuters rankings, with Mergermarket recording a 103.9 percent increase in total deal value, to $317.6 billion, for the firm’s clients.

As The Am Law Daily has reported in the past, the three outlets rely on different measures when compiling their rankings—a fact that renders the lists useful mostly as a broad gauge of which law firms are most active in the M&A market.

The reports also offer a look at the pace of M&A activity as a whole, with Mergermarket noting that deal confidence was building throughout 2013 before a “lackluster” fourth quarter saw overall deal value drop 12.7 percent from the third quarter, to $570.5 billion worth of transactions. Bloomberg, meanwhile, reported that global M&A deal volume fell 27.8 in the fourth quarter compared to the same period in 2012 after increasing 36 percent year-over-year in the third quarter. Overall, global M&A deal volume dipped 3.2 percent to $2.2 trillion in 2013 compared with the previous year.

Mergermarket points to the technology, media and telecommunications (TMT) sector as one area that saw enough deal activity to at least keep the global market static last year. Deal value in that sector rose 54.1 percent, to $510.1 billion last year compared to 2012. Driving that increase was the third-largest transaction in history: Verizon Communications’ $130 billion purchase of Vodafone Group’s 45 percent stake in Verizon Wireless. Announced in September, the deal included roles for all three of the league table leaders. Wachtell served as lead counsel to Verizon Communications and Simpson Thacher advised Vodafone. Davis Polk, meanwhile, represented J.P. Morgan Securities and Morgan Stanley, both of which served as financial advisers to Verizon on the matter.

The three firms also grabbed roles on the $25 billion take-private sale of Dell to its founder Michael Dell, which was announced in February and faced a number of bumps before becoming official in October. Also announced in February was the megadeal that saw billionaire Warren Buffett’s Berkshire Hathaway team up with Brazilian private equity firm 3G to buy H.J. Heinz company for $28 billion. Davis Polk advised Heinz on that deal, while Wachtell took the lead for a special committee of that company’s board of directors. More recently, Wachtell was one of seven firms advising on the sale of Cole Real Estate Investments to American Realty Capital Properties in an $11.2 billion REIT deal announced in October.

While those three firms came out on top based on their clients’ deal volume, the three outlets’ league tables also ranked legal advisers based on total deal count for 2013. In those rankings, both Bloomberg and Thomson Reuters tabbed Jones Day as the top firm based on total number of transactions announced during the year, with 412 and 369, respectively. DLA Piper topped Mergermarket’s end-of-year deal count with 385 transactions.