The article discusses how firms use equity and debt as options on their assets, with shareholders holding call options and lenders selling put options. Structural models have been developed to assess credit risk using accounting and equity market data. These models have increased interactions between asset classes, leading to a more coherent market continuum. While these models improve asset price formation, oversimplification and excessive confidence in their signals should be avoided. Structural models provide additional tools for analyzing credit risk but should not replace existing methods.