The Mark to Market methodology is used to compute a value closest to the fair value of an asset or security, by marking it at its market value. Mark to market should be reported daily and the increase and the decrease in the MTM should be reported daily in the P&L. When positions are cleared through a Clearing House, the central counterparty is in charge of re-evaluating positions at their current market price at the end of each day. The re-evaluation of the portfolio will then be used to make calls for new margin (margin calls).