Here we have it. The best private equity house clients in Europe are the following: Kohlberg Kravis Roberts & Co (KKR), Permira, Apax Partners, Blackstone and Macquarie Bank.

Some may disagree with this, but new Mergermarket rankings show that the five buy-out houses have worked on the greatest value of deals in Europe during the past three years.

KKR easily topped the list by value, having undertaken E66.3bn (£46.2bn) worth of European deals since October 2004, significantly aided by its £9.7bn acquisition of Alliance Boots earlier this year. Second-placed Permira secured 23 deals worth a total of E40bn (£27.9bn) and Apax came third with 34 deals worth E38bn (£26.5bn) under its belt.

All this is good news for a surprisingly large group of advisers. To name but a few, these include Clifford Chance (CC) for KKR, Permira and Macquarie; Ashurst for Apax and Blackstone; Freshfields Bruckhaus Deringer for Permira and Apax; and Simpson Thacher & Bartlett for KKR and Blackstone.

Dig a little deeper – especially into Europe – and a whole host of new firms are unearthed. Linklaters, for example, is developing strong ties with Permira in Spain and Italy, as well as nurturing a growing relationship with Macquarie in France.

The growth of the buy-out market, the number of auctions, the resulting conflicts and the increase in cross-border work have provided a host of opportunities for advisers to get to know new clients.

There is one place where near-exclusive client relationships still exist – New York. But this is not helping US firms much in Europe, where they face an uphill battle to hold on to these relationships in the face of stiff competition from full-service European advisers.

True, Simpson Thacher plays a 'quarterbacking' role on most of KKR's and Blackstone's European deals. But UK lawyers are confident such US links will fade as these houses hire increasing numbers of local deal-doers.

Then again, it is not just US firms that are in danger of having their market share eroded. At the turn of the millennium, before private equity deals really mushroomed, today's level of client-sharing was virtually unheard of in the UK. Back then, CC and Ashurst dominated the market thanks to the exclusive relationships they enjoyed with many of the most important houses. Indeed, even as recently as 2003, near-exclusive CC clients Permira and CVC were the most active buy-out houses for European M&A.

Nowadays none of the advisers have a monopoly on their clients. As one partner at a leading private equity firm puts it: "Everybody's market share has dropped a bit, but the market has grown so much that it doesn't really matter."

But, while acting for the leading private equity houses is no longer quite the prize it used to be, competition to get in with them is only likely to intensify.