In conditional dealings, the shares shot up as high as 191p, valuing Mr Coombs's 57 per cent stake at £771 million and the entire business at £1.35 billion, virtually assuring its place in the FTSE 250 club of London-listed midcap stocks.

Goldman Sachs and UBS had set an indicative price range of 142-170p, but investors have lapped up the 25 per cent of the business being sold, the minimum allowed under listing rules.

Ashmore specialises in investing in bonds and equities in emerging markets on behalf of institutional investors like pension funds. it has more than $20 billion under management and more than doubled profits last year to £104 million.

Mr Coombs bought the business for a peppercorn sum from his then employers ANZ in 1999, shortly after the Russia default crisis - which smashed investor confidence in emerging markets and so depressed the price of Ashmore.

He has sold a quarter of his holding at the 170p placing price, netting him £172 million in cash. His 52 colleagues have also sold a quarter of their holdings, as has the private equity player John Moulton.

Directors and staff are stressing to new investors that they have kept 75 per cent of their holdings, which are subject to lock-up restrictions, giving them very large stakes in the future success of the business.

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