Mondaq.com has an article by Katherine Shea of Cains, Solicitors of the Isle of Man, which says:

Latest figures released by research agency Hemscott show that, of the non-UK top 100 companies listed on the London Stock Exchange Alternative Investment Market (AIM), by far the greatest number are incorporated in the Isle of Man, equal to second-placed Bermuda, Canada and Guernsey combined. On the basis of market capitalisation, the Isle of Man again leads the non-UK jurisdictions, with second-placed Canada having just over a third of the Isle of Man's total. The Isle of Man also occupies the top spots in the All-AIM tables having (jointly with Guernsey) the greatest number of companies and a clear lead on the basis of market capitalisation, followed by Canada then Guernsey. In particular, the BRIC economies (Brazil, Russia, India and China), together with an increasing number of Eastern European players, have seized the advantages offered by the Isle of Man (including tax neutrality, the absence of a need for regulatory pre-approval, plus its 'AAA' credit rated economy) to access London and other major exchanges.

Depressing isn't it that someone can so celebrate the movement of capital to a location where 'tax neutrailty' actually means 'no tax' (a term too offensive for people in the IoM to use as it would require them to admit that they are a tax haven) and that they are institutionally relocating profits to ensure that tax compliance does not take place.

Sad too that Canada (a haven for these purposes), Bermuda and Guernsey are next.

No wonder that the FT has noted the relative lack of confidence in the regulatory approach of British stock markets.