ABSTRACTThe share of secured debt issued (as a fraction of total corporate debt) declined steadily in the United States over the twentieth century. This stems partly from financial development giving creditors greater confidence that high‐quality borrowers will respect their claims even if creditors do not obtain security upfront. Consequently, such borrowers prefer retaining financial flexibility by not giving security up front. Instead, security is given contingently—when a firm approaches distress. This also explains why, superimposed on the secular decline, the share of secured debt issued is countercyclical.