<t>Thanks for your answers. The percentage difference is quite big. Maturity date is 24.1.2013, paying Euribor12 - 24,5bp, receiving Euribor3 flat, Nominal = 170mEUR. SWPM gives a PV of -2,2m? and my counterparty is saying -1,7m?... The effect of changing to OIS discounting is quite minimal (about 3...