Agency problems limit firms' access to capital markets, curbing investment. Firms and investors seek contractual ways to mitigate these problems. What are the implications for investment? We present a theory of a firm's investment dynamics in the presence of agency problems and optimal long-term financial contracts. We derive results relating firms' investment decisions, current and past cash flows, firm size, capital structure, and dividends. Among the results, optimal investment is increasing in current and past cash flow; and optimal investment is positively serially correlated over time (after controlling for investment opportunities). These results hold for a range of agency problems.

We characterize equilibrium leverage dynamics in a trade‐off model in which the firm can continuously adjust leverage and cannot commit to a policy ex ante. While the leverage ratchet effect leads shareholders to issue debt gradually over time, asset growth and debt maturity cause leverage to mean‐revert slowly toward a target. Investors anticipate future debt issuance and raise credit spreads, fully offsetting the tax benefits of new debt. Shareholders are therefore indifferent toward the debt maturity structure, even though their choice significantly affects credit spreads, leverage levels, the speed of adjustment, future investment, and growth.

We analyze the optimal trading and ownership policy of a large shareholder who must trade off diversification and monitoring incentives. Without commitment, the problem is similar to durable goods monopoly: the share price today depends on expected future trades. We show that the large shareholder ultimately trades to the competitive price‐taking allocation, even though it entails inefficient monitoring. With continuous trading, the large shareholder trades immediately to this allocation if moral hazard is weak enough that her private valuation of a share is decreasing in her stake. Otherwise, the large shareholder adjusts her stake gradually. We consider implications for asset pricing, IPO underpricing, and lockup provisions.

A privately informed seller seeks to liquidate a portfolio to raise cash. Each asset’s liquidity thus depends on the impact of its sale on the value of the entire portfolio. We demonstrate the importance of cross-signaling and derive sufficient conditions for a liquidity “pecking order” that determines the order of sale. For assets backed by a common pool, liquidity naturally aligns with seniority. Finally, we extend the portfolio liquidation game to consider security design and demonstrate the optimality of pooling securities and selling senior tranches or debt secured by the pool, with retention increasing in asset quality or informational asymmetry.

Self-regulation is a feature of a number of professions. For example, in the U.S. the government delegates aspects of financial market regulation to self-regulatory organizations (SROs) like the New York Stock Exchange and the National Association of Securities Dealers. We analyse one regulatory task of an SRO, enforcing antifraud rules so agents will not cheat customers. Specifically, we model contracting/enforcement as a two-tier problem. An SRO chooses its enforcement policy: the likelihood that an agent is investigated for fraud and a penalty schedule. Given an enforcement policy, agents compete by offering contracts that maximize customers' expected utility. We assume that the SRO's objective is to maximize the welfare of its members, the agents. We show that the SRO chooses a more lax enforcement policy—meaning less frequent investigations—than what customers would choose. A general conclusion is that control of the enforcement policy governing contracts confers substantial market power to a group of otherwise competitive agents. We also investigate government oversight of the self-regulatory process. The threat of government enforcement leads to more enforcement by the SRO, just enough to pre-empt any government enforcement.

Existence of equilibrium with incomplete markets is problematic because demand functions are typically not continuous. Discontinuities occur at prices for which a marketed asset suddenly becomes redundant. The authors show that this discontinuity disappears if they allow an agent in the economy to introduce a new asset when such redundancies occur. This enables them to prove generic existence with incomplete markets using a standard path-following argument. Moreover, the authors' approach suggests a simple algorithm for computing equilibria when markets are incomplete. They demonstrate this by computing equilibrium for a numerical example.

Regulating insider trading lessens the adverse selection problem facing market makers, enabling them to quote better prices. An Optimal enforcement policy must balance these benefits against the costs of enforcement. Such a policy must specify (i) the conditions under which the regulator conducts an investigation, (ii) the penalty schedule imposed if an insider is caught, and (iii) a transaction tax to fund enforcement. We derive the policy that maximizes investors welfare. This policy entails investigations following large trading volumes or large price movements or both. Insiders caught making large trades are assessed the maximum penalty, but small trades are not penalized. Given this policy, insiders trade most aggressively on news with an intermediate price impact but refrain from trading on moderate or extreme news.

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.

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.

We introduce dynamic agency into the neoclassical q theory of investment. Costly external financing arises endogenously from dynamic agency, and influences firm value and investment. Agency conflicts drive a history-dependent wedge between average q and marginal q, and make the firm’s investment policy dependent on realized profits. A larger realized profit induces higher investment, and hence a larger firm. Investment is relatively insensitive to average q when the firm is “financially constrained ”(i.e. has low financial slack). Conversely, investment is sensitive to average q when the firm is relatively “financially unconstrained,” (i.e. has high financial slack). Moreover, the agent’s optimal compensation is in the form of future claims on the firm’s cash flows when the firm’s past profits are relatively low and the firm has less financial slack, whereas cash compensation is preferred when the firm has been profitable, agency concerns are less severe, and the firm is growing rapidly. To study the effect of serial correlation of productivity shocks on investment and firm dynamics, we extend our model to allow the firm’s output price to be stochastic. We show that, in contrast to static agency models, the agent’s compensation in the optimal dynamic contract will depend not only on the firm’s past performance, but also on output prices, even though they are beyond the agent’s control. This dependence of the agent’s compensation on exogenous output prices (for incentive reasons) further feeds back on the firm’s investment, and provides a channel to amplify and propagate the response of investment to output price shocks via dynamic agency.