LONDON (Reuters) - U.S. investment bank Goldman Sachs has opened up a $100 billion lead in this year’s worldwide M&A league table after grabbing advisory roles on the top four deals in this week's bumper week for takeovers.

Deals this week, the busiest so far this year, were worth $140 billion, lifting year-to-date M&A activity to almost $1 trillion, according to Thomson Reuters data. That is up 25 percent from a year ago and the strongest start to a year since 2007.

Goldman advised on deals worth $119 billion that were announced this week. It worked for Mylan on its offer for Perrigo, BG Group in its takeover by Shell, TNT Express in its $4.3 billion bid from Fedex and Permira Advisers and the Canada Pension Plan Investment Board in its proposed $4.5 billion buyout of Informatica Corp.

Goldman has advised on 99 deals worth $305.8 billion so far this year. Bank of America Merrill Lynch has moved up into second spot with deals worth $207.2 billion and JPMorgan slipped to third with $188.8 billion of deals, Thomson Reuters data show.

Advisory boutique firm Robey Warshaw has jumped to eighth spot in the M&A league tables after also working with BG Group.

(Reporting by Steve Slater; Editing by Elaine Hardcastle)