In a trading update issued Monday, the vendor describes the current market conditions as "exceptional" and says that while buying cycles have yet to see a decline, "we do not believe we can be immune to any impact".

It says the slowdown in the sales pipeline for Fidessa LatentZero, reported in its interim results, has passed with recent orders being within expectations. Any shortfall in revenue has been offset by strong continued demand elsewhere in the group.

Nonetheless, Fidessa chief Chris Aspinwall cautions: "We are currently operating through unprecedented market conditions, which are inevitably having an impact on forward visibility."

The vendor has booked a debtor exposure of £.06 million related to the collapse of Lehman Brothers, which was a top ten customer and warns of an additional risk to 2008 revenue of up to £1.3 million. The firm says it is negotiating with "the parties concerned" to reduce this exposure and risk.

David Toms, an analyst at Numis Securities has estimated that approximately one-fifth of Fidessa's client base could disappear as institutions consolidate and that half of the remainder would halt all development work in 2009.

Despite the gloomy prognosis, shares in Fidessa firmed up slightly from an opening year low of 573 pence to a mid-morning price of 585 pence.