To be or not to be included in the S&P 500: cost of debt implications

Purpose: We examine the changes in a firm’s cost of debt after it is included in or removed from the S&P 500. The extant literature on index composition focuses on the cost of equity and lacks an understanding of the impacts on a firm’s cost of debt capital upon inclusion in or removal from a major stock market index. Therefore, we address the following question: Does a firm’s cost of debt change around its inclusion in or removal from the S&P 500? Design/methodology/approach: We develop two hypotheses based on the research question and use univariate and multivariate fixed-effects analyses to test them. Furthermore, to ensure robustness and address endogeneity concerns, we employ a matched control sample difference-in-difference statistical framework. Findings: Inclusion in the S&P 500 lowers a firm’s cost of debt by 0.145% and 0.200%, on average, in the six- and three-month periods after inclusion. Furthermore, after a firm is removed from the index, a firm’s cost of debt increases on average 0.380% and 0.260% in the six- and three-month periods in the post-inclusion period when compared to the pre-inclusion period. Originality/value: This study contributes novel insights into the cost of debt and index composition literature. It provides insights for academics, investors, creditors, corporate managers and index selection committees.