The committee's preliminary report was being discussed with all parties, and it was not known whether the findings would be made public, a spokeswoman for the exchange said.
Complaints against Warburg followed Enterprise's controversial share raid to acquire 10 per cent of Lasmo. A number of the target's shareholders are believed to have placed sell orders which were ignored when Enterprise went into the market.
The preliminary ruling is said to relate to a complaint by Swiss Bank Corporation that the share raid, led by Warburg, favoured institutions more supportive of the pounds 1.6bn bid. Warburg, which has drawn criticism for misjudging the market's mood during the bid, denied unfair treatment of shareholders.
Stock Exchange regulations say that all pre-placed orders should be executed first.Reuse content