The topline of the country’s top four software exporters — TCS , Infosys, Wipro, Satyam —could exceed projections by between 3.3 per cent and 6.3 per cent if the trend of depreciation in the value of the rupee against the US continues, a report by Angel Broking says.

The rupee has depreciated by 6.76% against the dollar since the beginning of this fiscal. It closed at 42.54/55 on the interbank forex market on Friday.

The report, authored by Harit Shah, said India’s biggest IT services exporter, TCS, would top its revenue guidance for the fiscal by 3.8 per cent at a conversion rate of Rs 41 and by 6.3 per cent at Rs 42. Satyam’s revenues are seen beating guidance by 3.6 per cent at an exchange rate of Rs 41 and by 6.1 per cent at Rs 42.

Infosys and Satyam, the country’s second and fourth largest software companies, respectively, have factored an exchange rate of Rs 40 while projecting revenue guidance for the fiscal. The EBIDTA (earnings before interest, depreciation and taxes) margins of all four companies are expected to rise by 1.1 per cent at Rs 41 and by 1.9 per cent at Rs 42. For the year-ended March 2008, Infosys reported a topline of Rs 21,447 crore, TCS Rs 29,372 crore and Satyam Rs 10,986 crore.

The report also cautioned that depreciation of the rupee was temporary and that the brokerage expects a 4 per cent appreciation during 2009-10. Furthermore, with uncertainty about world economic growth continuing, there could be some cooling off in volume growth, at least during the first half of the current fiscal, the report says.