For T+1 and T+2 settled orders, settlement date may be deferred when there is a holiday after trading day.
Detailed rules are:
If either transfer to currency or transfer from currency or USD has a 'holiday' on the target settlement date, settlement is deferred until the next valid business day for all currencies.
For example, 9 August 2024 is a SGD holiday, if client performs a conversion on 7 August 2024; which is T+2 settled, then it will be settled on 12 August, because 9 August is SGD holiday, while 10 August and 11 August are weekends.
Intervening holidays (that is a holiday between trade date and the standard 2 days later) for the transfer to currency and transfer from currency, also defer settlement dates.
For example, 2 September 2024 is a USD holiday. If the client performs a conversion on 30 August 2024, which is T+2 settled, then it will be settled on 4 September, because 31 August, and 1 August are weekends, while 2 September is USD holiday.
Currency Holiday Calendar (For reference only)