Unusual restrictions have been imposed on private investor participation in the $2bn debut of UC Rusal on the Hong Kong stock market, the first initial public offering by a Russian company in the territory.

The Securities and Futures Commission, the Hong Kong regulator, has insisted on a minimum entry level of HK$1m ($130,000) for those wishing to buy into the aluminium group's IPO, according to two people close to the transaction.

To discourage small investors further from participating in the secondary market, Rusal will be traded on the exchange in lots of 200,000 shares. The SFC, which has not yet formally announced its decision, decided at the last minute to double the threshold, having earlier indicated it would accept lots of 100,000 shares.