From what I recall from when I worked in FX trading, settlement dates were set by contract and not by regulations. As an aside calculating settlement dates for

From what I recall from when I worked in FX trading, settlement dates were set by contract and not by regulations. As an aside calculating settlement dates for currencies is actually pretty hard because different currencies have different rules, observe different holidays and roll-over differently. When calculating for a cross-pair you basically need to find the first settlement date which is a valid trading date for both currencies (except some currency pairs which have special rules).