Worldwide mergers and acquisitions activity has reached $2 trillion so far this year, 75 percent higher than last year, according to Thomson Reuters weekly data, helped by a string of large-cap companies striking high value deals.

Eight deals valued at more than $5 billion were announced this week, setting an all-time record for weekly deal making among companies with a large market capitalization, Thomson Reuters said on Friday.

The total value of deals over $5 billion hit $915.9 billion in the year to July 17, more than triple the level seen a year ago.

One such deal came on Tuesday, when Camel cigarettes maker Reynolds American said it would buy rival Lorillard for $26.8 billion. As part of the takeover, Britain's Imperial Tobacco Group bought a number of brands and assets from both companies for $7.1 billion.

Imperial adviser Goldman Sachs ranked at the top in the M&A league tables, ahead of Morgan Stanley and Citi.