This paper looks at the nature and evolution of contract securities or guarantees and the vulnerability of sureties who give such securities, being some of the most commonly used in the commercial world. There is a distinct and complex body of law relating to these securities which are surrounded by uncertainties and evolving concerns despite the growth and impact of consumer protection and credit legislation. Such securities or guarantees which are undertakings to answer for another’s default on a debt are signed by sureties in situations where they have little information about important aspects of the contract. It is not often, for example, that sureties have sufficient information about the borrowers’ loans or the financial health of their business. Such knowledge is invaluable if sureties are to give a fully informed consent to participate in the transaction. Also the vulnerability of the sureties is evident where pressure, coercion or undue influence from the financial institution may affect the former’s judgment so that they are not then in a position to act in a completely independent manner, and being fully aware of the risks involved. The paper also examines some of these issues in comparative perspectives.