This paper studies the relation between discrete–time and continuous–time principal–agent models. We derive the continuous–time model as a limit of discrete–time models with ever shorter periods and show that optimal incentive schemes in the discrete–time models approximate the optimal incentive scheme in the continuous model, which is linear in accounts. Under the additional assumption that the principal observes only cumulative total profits at the end and the agent can destroy profits unnoticed, an incentive scheme that is linear in total profits is shown to be approximately optimal in the discrete–time model when the length of the period is small.

Firms’ inability to commit to future funding choices has profound consequences for capital structure dynamics. With debt in place, shareholders pervasively resist leverage reductions no matter how much such reductions may enhance firm value. Shareholders would instead choose to increase leverage even if the new debt is junior and would reduce firm value. These asymmetric forces in leverage adjustments, which we call the leverage ratchet effect, cause equilibrium leverage outcomes to be history-dependent. If forced to reduce leverage, shareholders are biased toward selling assets relative to potentially more efficient alternatives such as pure recapitalizations.

ABSTRACT Firms’ inability to commit to future funding choices has profound consequences for capital structure dynamics. With debt in place, shareholders pervasively resist leverage reductions no matter how much such reductions may enhance firm value. Shareholders would instead choose to increase leverage even if the new debt is junior and would reduce firm value. These asymmetric forces in leverage adjustments, which we call the leverage ratchet effect , cause equilibrium leverage outcomes to be history‐dependent. If forced to reduce leverage, shareholders are biased toward selling assets relative to potentially more efficient alternatives such as pure recapitalizations.