Outsourcing giant Serco will tell investment analysts on Tuesday to stick with their full-year estimates, as nothing much has changed since its last trading update on 9 May."For 2011, we expect good organic revenue growth and progress towards our 2012 margin guidance," the company said in its pre-close statement. The group is targeting an increase in revenue to about £5bn by the end of 2012, while it has set its sights on a rise in adjusted operating profit margin to around 6.3%. Both forecasts exclude material acquisitions, disposals and currency effects."We remain encouraged by the developments in our markets across the world. However, as previously noted, the market in the UK remains challenging, with short-term headwinds resulting from government austerity measures, together with some uncertainties regarding public service reform," the statement said. --jh