Disclosed are arrangements for selling property off the plan, involving issuing (in a step ‘8’ in FIG. 6) an undertaking from a bank of a purchaser in favour of the developer from whom the property is to be purchased. The undertaking may be assigned (in a step ‘12’ in FIG. 6) to the developer's bank. The undertaking is legally enforceable by the assignee (in a step ‘15′’ in FIG. 6) if the purchaser, notwithstanding the fact that the developer has completely fulfilled the contractual obligations, defaults on his obligation at settlement.