The Chicago Board of Trade is to launch a new set of all-electronic gold and silver futures contracts in a bid to challenge the New York Mercantile Exchange's stronghold on the precious metals derivatives markets.

The new "full-sized" contracts will start trading in October alongside the Chicago exchange's existing mini-sized gold and silver futures which are also traded electronically and which have seen a fourfold increase in volume so far this year. The move is the CBOT's second attempt this year to wrest away business from another exchange.