Robey Warshaw LLP, a two-year-old investment bank with less than ten employees, is about to share a massive payday with two of Wall Street’s largest firms.

As an adviser to BG Group Plc on its sale to Royal Dutch Shell Plc, the London-based firm will split as much as $90 million in fees with Goldman Sachs Group Inc., according to estimates from Freeman & Co. Because of its size, Robey Warshaw may receive a smaller chunk of that amount.

Also set for a large payout is Bank of America Corp., which was the only adviser to Shell and could reap as much as $65 million for its work. The 47 billion-pound ($70 billion) deal is the largest takeover announced in 2015, and the oil and gas industry’s biggest merger in at least a decade.

Robey Warshaw is one of a handful of boutiques -- including Zaoui & Co. and LionTree Advisors LLC -- that have sprung up in recent years as some of New York and London’s top dealmakers left major institutions, winning mandates on large deals even without the resources of a major bank.

Started in 2013 by London bankers Simon Robey and Simon Warshaw -- veterans of Morgan Stanley and UBS Group AG -- Robey Warshaw also served as an adviser to AstraZeneca Plc as it resisted a takeover approach from Pfizer Inc.

Shell’s purchase is adding to what’s proving to be an already robust year for M&A advisers -- with about $327 billion in deals struck by European companies alone. That total is set to rise as the euro’s decline against the dollar and renewed confidence in an economic recovery make Europe appealing for global acquirers.

Goldman Sachs, which also advised on Ball Corp.’s acquisition of Rexam Plc, holds the top spot for merger advisory services in Europe this year. Bank of America is ranked second while its role on the Shell-BG deal has vaulted Robey Warshaw to third, data compiled by Bloomberg show.

Julian Mylchreest, global co-head of energy and power investment banking and Simon Mackenzie Smith, chairman of U.K. and Ireland corporate and investment banking, led Bank of America’s team on the deal. Goldman Sachs’s team was represented by Karen Cook, a London-based partner, and Mark Sorrell, co-head of U.K. investment banking.

Bank of America also provided a 3.025 billion pound loan to Shell to help fund the purchase of BG, Shell said in a statement on its website.

Goldman Sachs and Bank of America also advised on Halliburton Co.’s purchase of Baker Hughes Inc. last year, with Goldman representing Baker Hughes and Bank of America and Credit Suisse Group AG working with Halliburton, according to the data.

Crude oil’s decline since mid-2014 had heightened speculation that some of the largest names in the industry may look to combine their operations. Houston-based Halliburton, the second-biggest oil-services provider, agreed to buy Baker Hughes for about $35 billion in November. Most other acquisitions have been of small and medium-sized explorers.