Settlement Window

A settlement window is a defined period of time during which a payment or settlement system carries out settlement, or during which participants must make the payments needed for settlement to take place. Many systems that do not settle continuously instead settle in one or more windows during the business day, each with its own cut-off for submitting payments, a time when net positions are calculated and a time when funds move between participants' accounts. The term is common in automated clearing houses, net settlement systems and foreign exchange settlement.

A settlement window is different from a settlement period. The settlement period is the number of days between agreeing a trade or payment and settling it, while the settlement window is the slot within a day when settlement actually happens. A transaction with a one-day settlement period may still need to fit into a particular window on that day.

Think of a bus that leaves the stop at set times. Passengers who arrive before the bus leaves get on; those who arrive late wait for the next one. A settlement window works the same way for payments. Instructions that reach the system before the cut-off ride the next settlement; anything later waits for the following window or the next day.

Some systems run a bus every few minutes, others only a few times a day, and some only once. Each window is also a moment when banks must have enough money in place to pay what they owe, much like having a ticket ready when the bus arrives.

A typical window in a net settlement system runs through a sequence of steps:

1. Participants submit payments up to a cut-off time for that window.
2. The operator closes the window to new items and uses multilateral netting to calculate each participant's net position.
3. Participants with net debit positions make sure funds are available, sometimes by paying in to a settlement account by a deadline.
4. The settlement institution, often the central bank, posts the net positions to participants' accounts, and settlement becomes final.
5. The operator releases results and participants post entries to their customers' accounts.

Systems that settle each payment individually, such as real-time gross settlement systems, have an operating day rather than windows, but they often reserve set times for particular activity, such as other systems settling their net positions.

• US ACH. The automated clearing house (ACH) network settles in a series of windows each business day. Same Day ACH, which now offers three same-day windows, lets payments settle on the day they are sent as well as on the following day.
• UK Bacs. Bacs processes payments over a three-day cycle, with interbank settlement on the third day at the Bank of England.
• UK Faster Payments. Customer payments under Faster Payments are credited within seconds, but the banks behind them settle their net positions at the Bank of England in several settlement cycles each business day.
• CLS. CLS settles foreign exchange trades during a daily window of a few hours, chosen because it overlaps the operating hours of the RTGS systems for all its currencies. Members make pay-ins on a schedule during the window, and trades settle on a payment-versus-payment basis.
• Ancillary systems in T2. Net settlement systems such as card schemes and retail clearing houses settle their positions in the Eurosystem's T2 through scheduled settlement procedures.

Windows shape both risk and liquidity. Between windows, participants in a deferred net settlement system have unsettled positions with each other, so more frequent windows shorten the time any participant is exposed. Each window, though, needs participants to have funds ready at the right moment, which places demands on their intraday liquidity management. Operators choose the number and timing of windows to balance these needs against operating costs.

Windows also define service levels for customers. A business that sends a payment just after a cut-off may find it settles hours later, or the next day. Banks publish their own internal cut-offs, usually earlier than the system's, to leave time for checks.

A participant that cannot meet its settlement obligation in a window can delay settlement for others. Systems manage this with prefunding, collateral, debit caps and backup procedures, and they plan how to extend or reopen a window if there is an operational outage. Clear rules on when settlement finality occurs within each window are essential, so that participants know when they can treat incoming funds as their own.

• Nacha
• CLS Group