Hello to everyone. I have a theoretical question that bothers me for a while: how does the interest rate assumptions that are embbeded into a European style cash-settled box spread are being determined? For example, if there is a box spread which is 10 points apart which expires within one year, does its price should exactly reflect the current yeild on a one-year tresuary (which is about %0.15, so that the box price should be no higher or lower than 9.985)? Does the box price can reflect interest rates that are substantially different from a one-year treasury and if so on what benchmark it may be based (i.e., any specific benchmark other than the treasury yield, the trader's own cost of borrowing/lending or any other benchmark)? Thanks in advance for any feedback.