(b) all initial and subsequent deposits for margin purposes shall be made in USD, or another currency which ATM Capital may choose to accept, in such amounts as ATM Capital may in its sole discretion require, with subsequent deposits being in the same currency as the initial deposit; and (c) ATM Capital is authorized to convert funds in Customer’s Account for margin into and from such foreign currency at a rate of exchange determined by ATM Capital in its sole discretion on the basis of then prevailing money market rates.