Software developer Autonomy is expected to crash out of the FTSE100 on Wednesday when the London Stock Exchange revises its list of top stock performers.Over recent weeks the company's valuation has dropped from £4.4bn to £1.5bn after city analysts fell out over their assessment of the stock. Questions surrounding its technology, quickly followed by the sale of a seven per cent stake by one of its backer's, Apax Partners, lead to the downgrading of its stock. Autonomy's descent continued as rumours surfaced that Microsoft was poaching staff to develop a rival product. Shares fell more than 10 per cent on the news. However, Autonomy is not the only company to suffer the fate of the stock market. Electricity producer International Power, now valued at £2.58bn, will also be kicked out. New comers include brewers Scottish and Newcastle and IT services company Sema. However, Sema's position at 87 with a valuation of £3.36bn is expected to be short lived in light of the soon to be completed takeover by Schlumberger. The company has also issued two recent profit warnings. The revised Index will start trading on Monday 19 March.