(4)In view of the considerable price differences of financial instruments in the multiple underlying transactions and in order to facilitate the calculation of cash penalties, the value of financial instruments should be based on a single reference price. The same reference price should be used by CSDs on a given day for calculating cash penalties for settlement fails concerning identical financial instruments. Cash penalties should be therefore the result of multiplying the number of financial instruments underlying the transaction that failed to settle by the relevant reference price. The establishment of reference prices should be based on objective and reliable data and methodologies.