A number of applications - believed to have been more than 10 - were refused because the investors had been trying to depress the price in the run-up to the offer by selling shares they did not own.
Laurence Banks, of Robert Fleming, global co-ordinator of the issue, said that most of the short-selling was done by 'individuals, groups of individuals and hedged funds in the US'.
No British institutions had sold short, although a number had sold during the flotation period. 'Those who did were less well treated in the application process,' Mr Banks said.
Applications for 360 million shares were received, but the trust decided to scale back the offer to help ensure a stable after-market for the shares. When it launched the prospectus in June it had hoped to sell 330 million.
Up to 40.5 million more shares could be issued by the trust under a price stabilisation mechanism to be operated by Fleming over the next 30 days.
These extra shares have been allocated to investors, but can be bought back by Fleming if the price drops below 800p.
British investors, who accounted for 55 per cent of the demand, were allocated about 60 per cent of the shares offered while US investors took 70 million compared with 80 million applied for. The 14.4 million applications from retail investors were met in full.
Trading in the US was brisk, with more than 11 million shares changing hands in the first two hours. A number of German investors are also believed to have sold shares. About 200 US institutions were allocated shares, making it one of the most successful offerings by a British company.
Roger Gibbs, chairman of the trust, said up to 40 per cent of the proceeds - almost pounds 1bn - would be invested in British equities, with the remainder in fixed interest stocks. The sale will double the charity's income to pounds 220m.
Some of the investment will be through an indexed fund being set up by Barclays de Zoete Wedd Investment Management. Its securities arm said the special dealing facility, designed to provide shares for the fund, had gone well.
Some of the trades under the special buying programme were incorrectly reported to the Stock Exchange, which meant dealing volumes were initially mis-stated. The errors, which BZW blamed on systems failure, were subsequently corrected.Reuse content