Chicago-based BDT, founded in 2009 by former Goldman Sachs Group Inc investment banking vice chairman Trott, 56, manages investment funds of more than $8 billion, and also advises family and founder-led businesses on M&A deals, corporate governance and succession planning issues.

Trott, who works with wealthy families in Europe such as Italy's Agnelli family, plans to submit a request to operate to Britain's Financial Conduct Authority, one of the sources said, adding that it might take up to six months to get the regulator's blessing and begin operations in Britain.

A spokeswoman from BDT declined to comment on the firm’s growth plans. A spokeswoman for the FCA declined to comment.

Assuming it receives authorisation, required of any firm that wants to carry out regulated financial activities in the UK, London will serve as a strategic hub for Europe. The move is part of BDT's expansion which includes the launch of a New York base to cater to Wall Street's wealthy clans, the source said.

BDT has worked with wealthy families in the United States including the heirs of the Mars Inc fortune and the Walton family of Wal-Mart Stores Inc.

BDT's main focus in Europe is to help billionaires look for better ways of earning a return than simply handing their cash to family offices or fund managers, by advising them on M&A deals and other investments, one source said.

BILLIONAIRES WITH BUSINESS

Trott has said that BDT works exclusively with "billionaires with businesses", according to an interview in Fortune magazine in December 2014.

During the financial crisis, Trott proved his friendship with one such billionaire - Warren Buffett - when he persuaded him to invest $5 billion in Goldman Sachs. It was Trott who brought Buffett into Mars Inc's $23 billion acquisition of Wm. Wrigley Jr. & Co in 2008, a deal in which Buffett invested about $6.5 billion.

Last year the number of billionaires in Europe overtook North America, with a third of the world's richest now residing on the continent, according to The Wealth-X and UBS Billionaire Census.

BDT & Company International was incorporated in Britain on Aug. 10, according to a filing in Companies House.

In Europe, BDT has already advised on some high profile transactions. Together with Morgan Stanley, it advised Exor SpA, the investment vehicle of Italy's Agnelli family, on its $6.9 billion acquisition of reinsurer PartnerRe.

After the PartnerRe deal was agreed in August, Trott hired Morgan Stanley co-head of mergers and acquisitions for the Americas, James Head, who left the U.S. investment bank in October.

Head will be based in New York helping Trott establish BDT's brand further among Wall Street clients, two sources said.

BDT also co-invested and advised German investor Joh A Benckiser (JAB) in 2013 on the acquisition of Dutch coffee company Douwe Egberts which later merged with Mondelez's coffee business to create Jacobs Douwe Egberts.

Trott is looking for a senior and seasoned dealmaker who has strong relationships with high net worth individuals across Western Europe, to lead the London office, according to another source.

Trott's boutique will need to position itself in a crowded market alongside the likes of Robey Warshaw, the tiny Mayfair advisory firm which has landed the two biggest merger deals of the year, clinching key roles for UK brewer SABMiller and oil and gas firm BG.      

BDT is planning to expand at the same time as former Morgan Stanley rainmaker Paul Taubman is looking to aggressively hire at his own boutique firm PJT Partners. Earlier this year PJT hired several senior European dealmakers for its own office in London.

BDT is ranked 66th in the M&A league tables so far this year, having advised on three deals worth $14.2 billion dollars, according to Thomson Reuters data. That compares with 108th position at the same time last year. ($1 = 0.9369 euros)

(Editing by Alexander Smith and Giles Elgood)

By Anjuli Davies, Pamela Barbaglia and Olivia Oran