This study analyzes the role of personal guarantees and collateral in the context of two different lending structures: one transaction and the other relationship based. The Finnish bank data, which were uniquely accessible for the study, enabled an exploration of credit files with specific details of the characteristics of the lending relationship during the period 1995–2001. According to the empirical results, the use of personal guarantees is an indication of transaction-based lending. Personal guarantees seem to increase the loan premium in transaction-based loans more than in relationship-based loans. Close ties between a bank and a firm seem to be a desirable basis for small and medium-sized enterprise bank lending.