HELLENIC EXCHANGES S.A.: Margin Parameter Change

As of Friday 04/07/2008 the fixed volatility parameter that RIVA uses for the margin calculation for the derivative products on the indices FTSE/ASE-20 and FTSE/ASE Mid-40 is being adjusted from 28% to 32%.

This change will come into effect for the open positions that will arise at the end of the trading session of 04/07/2008.