It is one of the most contentious issues in politics whether or not Scotland will continue to use the pound in the event of independence.
While the UK Government may say a shared sterling zone between an independent Scotland and the rest of the UK is unfeasible, some currency exchanges are already offering differing rates for Scottish and English banknotes.
An eagle-eyed Courier reader on a trip to New York spotted the currency exchange in the Waldorf Astoria paid $1.3429 for every English pound but marginally less, $1.3387, for Scottish notes.
The differing rates are nothing to do with Scotland’s future in or out of the UK, however.
Instead, Choice Forex, the company which sets the rates, said it was because there is less global demand for Scottish notes or anywhere else outside of England.
On its website, the company said it would pay $1.526 for every English pound but only $1.52145 for every Scottish pound.
Scottish and English notes are both worth far more than Isle of Man pounds, which were only worth $1.4647 on Thursday.
A spokesman for Choice Forex said: “They are the same currency and exactly the same value.
“When we have excess Scottish or Northern Irish notes we have to sell them off and the wholesalers pay us less. The notes are valued the same but there is a smaller market for them.”
A Treasury spokesman said: “There is no economic reason for currency dealers to offer a different exchange between two interchangeable notes such as these.”