Abstract: A computerized method provides periodic mark trading of financial instruments on a computerized trading system having one or more server computers. The method comprises at least one of the server computers: receiving a communication from a customer computer on a trading date, the communication including at least one periodic mark limit order, including at least an amount and an indication of a mark time at which a price will be determined for the at least one periodic mark limit order, and placing the received at least one periodic mark limit order in a periodic mark pool; calculating a periodic mark price from non-periodic mark orders on the book of an FX ECN; matching the received periodic mark limit order with a compatible other periodic mark limit order in the periodic mark pool; after the mark time, executing the matched received periodic mark limit order at the calculated periodic mark price.