Many individuals will use the terms Letter of Intent, Memorandum of Understanding, and Term Sheet interchangeably, however there are slight, mainly style, differences. Memorandum of Understanding (MOU): The main difference between the MOU and LOI is the nature of the signatories. While two parties are involved in a LOI, a MOU can involve more than two parties. Additionally, while a letter of intent needs only the party which proposes the agreement to be a signatory, a MOU implies that all the parties involved have to be signatories.
Such sellers would persistently demand that the prospective buyers hurry and issue them an LOI right upfront purportedly as proof that they are "serious" about making the purchase _ that is, before the buyer may probably start raising some probing questions about them or their credentials as legitimate sellers.