Practitioners now acknowledge the presence of several yield curves in the market for a given currency and now use different discounting curves to those used to calculate forwards.
The discounting curve is chosen in function of the funding method, usually OIS or 6M Libor. Nitrox consulting models integrates these discrepencies, matching the market's practices.
Nitrox Consulting models take into account currency basis swaps, hence eliminating possible arbitrages between positions in different currencies, a crucial tool for treasurers and multi-national institutions.
Optional derivatives operate along the SABR model which has now become the standard of the market. However the user has the ability to control the model parameters.