Given the nature of foreign exchange markets, there is no single interbank rate. Our interbank rate is determined by us having reference to live exchange rates from our banking partners and market data sources, and then calculating a blended rate from those sources. The blended rate may involve calculating the weighted average of one or more exchange rates available to us.
We don't include a markup specific to you in the interbank rate. However, foreign exchange markets generally only operate 5 days per week, Monday to Friday. During the weekend, and other times when markets are closed or where rates are unavailable to us, an additional markup may be applied to our interbank rate to account for such situations.