Kuwait's Amara Dhari Investments, with a 17.2% stake in Plus Markets, and Simon Chapman, a private investor with about 2.8%, have criticized Plus Markets' agreement to sell Plus Stock Exchange to Icap Management Services Ltd. for a symbolic £1, plus the assumption of liabilities. That transaction was sealed on May 18, just a few days after the parent company had warned it would have to wind down its operations after a strategic review failed to yield workable offers. Shortly after the Icap deal, Gulf Merchant Bank Ltd. said it had submitted a revised offer, which Plus rejected, refuting Gulf's suggestion that its proposal was worth substantially more than the Icap deal.

Plus Markets said it had already asked the Financial Services Authority to begin work on revoking Plus Stock Exchange's recognized investment exchange license if the Icap deal doesn't proceed.

"For the avoidance of doubt, in the event that the proposed disposal of PLUS-SX does not complete before 22 June 2012, for whatever reason, the FSA will commence the process as soon as possible to revoke the recognition order and this process is irreversible," it said. It said the revocation of the recognition order, which would strip Plus Stock Exchange of its ability to operate should the Icap deal not close, would take affect from Oct. 31.

Plus Markets shareholders meet to vote on the Icap deal on June 18.

Plus Stock Exchange was created to provide a third-tier exchange below the London Stock Exchange's Main Market and the Alternative Investment Market for smaller companies or those with a less well-established track record.

For Icap, an interdealer broker with a market value of £2.2 billion ($3.4 billion), the purchase of Plus Stock Exchange would provide a low-cost route to gaining a recognized investment exchange license amid a regulatory drive to push equities trading onto regulated exchanges.

If Plus Stock Exchange loses its RIE license, the 156 companies listed on the exchange would have to move to another exchange or seek alternative funding arrangements.

Plus Markets' other units include Plus Derivatives Exchange Ltd. and Plus Trading Solutions Ltd.

Plus Markets' advisers are Nplus1 Brewin LLP's Robert Beenstock, Aubrey Powell and Alex Wright and Wyvern Partners' Anthony Gahan.