The group, which represents about 130 organisations, said it was reopening discussions with several financial services companies to set up an Enterprise Market of its own.
The move has been prompted by growing fears that the Exchange has turned its back on the second-tier market despite a recommendation from its own working party for a successor to the USM, which is due to be closed at the end of 1995.
Last month the Exchange announced that it was commissioning market research to gauge the level of support for a new market. But the move triggered widespread criticism from City professionals.
'We have been messed around by the Exchange for far too long,' said Richard Balarkas, Cisco's chief executive. 'All the messages we get is that there is a real danger that it does not want to create a new market.
'Cisco would prefer that this proposed market be run within the Stock Exchange framework. However, we must anticipate the possibility that it may decide not to create one.'
As a result the group is reviewing plans, drafted more than a year ago, to create an alternative market that would provide trading and settlement of share dealings, a company news service and regulation. It is understood that Nasdaq, which operates New York's highly successful over-the-counter market, and Reuters are among leading contenders to provide the service.
The group hopes to finalise its plans within three months and have them ready by the time the Exchange has made up its mind.
Many City professionals believe the USM needs to be replaced by a more flexible forum that allows companies with little or no trading record to obtain a market quotation. They say it should also have simplified disclosure rules concerning acquisitions.
The campaigners believe the successor should have a separate supervisory board and management responsible for its regulation and promotion.
Cisco said its own research had shown that such a market would receive broad support from the City and industry. Some 90 per cent of its members backed the Enterprise Market and even more wanted to press ahead with an independent alternative if the Exchange declined to set one up.