This study highlights the need of considering the interaction effects between SMEs and the economic agents to determine the financial structure of Small and Medium Enterprises (SMEs). To get this purpose, we develop an empirical application on a sample composed by four hundred Spanish SMEs located in Murcia over the period 2007- 2012. With this information, we estimate a debt model applying spatial panel data methodology to test the significance of the spatial interaction effect in this context. Our results confirm the important role of spatial interactions in the financial analysis of reduced size companies.