The Chicago Board Options Exchange has added a second contract to its newly launched futures exchange, in spite of pending litigation from its rival, the Chicago Mercantile Exchange.

The CBOE's new future is based on the Standard & Poor 500 and comes as the CME which had filed a lawsuit against the CBOE over the latter's March launch of a contract based on the same index. The CME claimed the move "infringed" the exclusive licence agreement it has with Standard & Poor's to trade futures contracts based on the index.