When carrying a position over, the default behavior of Rithmic is to carry forward open positions into the new day at the close trade price of the prior day. This allows the user to see Day P&L in the Open P&L column. The Average Open Fill Price reported by the user is in fact the Close Trade Price of the instrument.
Ideally Rithmic would use the Settlement Price. However the Settlement Price is in many cases not published until after the new trading day has already begun. Given this fact, the Close Trade Price was the convention that the brokerage community asked Rithmic to adopt to show day p&l (normally the Settlement Price is very close to the Close). The trader is credited with the profit- or loss, and the position is carried forward at the close price. It is not a new position, it is the same position carried forward at a different cost basis. The profit (or loss) is added to (or deducted from) the cash.
P&L resets at the beginning of the new trading day for the product (not at the end of the old). The new trading day for NQ and many other products begins at 17:45 EDT, not 16:45 EDT. Please note that other products may begin their new trading day at a different time and that this time may be subject to change.
Additionally Stated: P&L is moved into cash and zeroed out during pre-open for the new day (5:45 pm EST). And, a new day is started. For instance, on a $10,000 account – if a trader has initiated a 1 contract trade and decides to hold the position for profit overnight and the trade is in profit $50 before the start of the new day, the account balance becomes $10,050 and the position and P&L of 1 contract is still open for the 1 position. For most products this will be moved into cash at 5:45 pm EST for the start of the new day, but traders should look at the contract specifications on the exchange website for operating hours which can and do change.
Example: On a 2500 daily loss limit account - if a trader has a trade that is $1000 dollar positive unrealized P&L and the market closes on the day and then reopens and drops $3000 dollars and the trader exits when the P&L is $2500 below the high account balance water mark then in this scenario a trader would be liquidated when the market dropped $2500 from the closing balance (which was the high account balance).
In a Performance Account, this is how it is handled: Note: In a Performance account, traders cannot carry positions over until discussed with Leeloo and the proper margin requirements have been met; therefore, all trades must be closed by 2:45 MST.
The FCM does not match off trades – First in First out. The first day you carry a position, they will carry the highest or lowest traded price, and will continue to carry that trade until position is flattened. This is simply an accounting method they use to give the account the highest possible value to be used for margin. It does not affect the balance of the account in any way. Once the Overnight run is processed and trades are matched off and statements are generated, the platform will adjust to coincide with the statements.