We solve the problem of valuing and optimal exercise of American call-type options in markets which do not necessarily admit an equivalent local martingale measure. This resolves an open question proposed by Karatzas and Fernholz (Handbook of Numerical Analysis, vol. 15, pp. 89–167, Elsevier,...

In a market with stochastic investment opportunities, we study an optimal consumption investment problem for an agent with recursive utility of Epstein-Zin type. Focusing on the empirically relevant specification where both risk aversion and elasticity of intertemporal substitution are in excess...

When the planning horizon is long, and the safe asset grows indefinitely, iso-elastic portfolios are nearly optimal for investors who are close to iso-elastic for high wealth, and not too risk averse for low wealth. We prove this result in a general arbitrage-free, frictionless, semi-martingale...

We examine dynamic contracts when output has negative environmental effects and the manager (agent) can invest to build up ESG capital and mitigate the externality. The incentive component of the optimal contract rewards based on cash flow and ESG capital when the principal is risk neutral; and...

We analyze the valuation partial differential equation for European contingent claims in a general framework of stochastic volatility models where the diffusion coefficients may grow faster than linearly and degenerate on the boundaries of the state space. We allow for various types of model...

We solve a model of firm dynamics with two states: cash and capital. The model high- lights how costly financing and default affect a firm’s cash management, investment, payout, and issuance policies. We find support in the data for new predictions: (1) issuance-to-capital ratios are...