Freshfields corporate partner William Lawes is not surprised by the success of the US offices working out of the UK.
He says: "A lot of the big companies do have US shareholders. If you do make an offer for them you have to abide by the US stock exchange rules. That is still the preserve of the big Wall Street firms."
The table comes days after Linklaters announced it was the first law firm in Europe to break the trillion-dollar barrier after acting on deals worldwide worth $1,064bn (£648.7bn).
It was involved in two of 1999's biggest deals: it is advising the Royal Bank of Scotland on its hostile bid for NatWest; and it is working on Vodafone's $148bn (£92.5bn) bid for Mannesmann - the largest unsolicited M&A deal ever.
Linklaters senior partner Charles Allen-Jones says: "For the first time, Europe saw a higher growth of M&A deals than the US. This may well be indicative for the year ahead."
Norton Rose's fifth position can mainly be attributed to its involvement with the Vodafone/Mannesmann bid - it is advising the German telecommunications giant.
Lawes concedes that all firms have benefited from changes in industry.
He says: "It is a factor of consolidation and growth in the value of companies.
"Given that the stock market is riding quite high, doing deals that you do through shares becomes quite cheap."