6.1 For the reasons explained in Chapter 5 there is a presumption that where an instrument is issued by a bank or other financial institution, or by an insurer or professional bond issuer, relating to an underlying transaction between parties in different jurisdictions, which contains an undertaking to pay ‘on demand’ and does not contain clauses excluding or limiting the defences available to a surety, it will be construed as a demand guarantee. Different considerations apply where the issuer of such an instrument is not a bank or other financial institution, an insurer or professional bond issuer.