Deep Hedging: Continuous Reinforcement Learning for Hedging of General Portfolios across Multiple Risk Aversions
Deep Hedging: Continuous Reinforcement Learning for Hedging of General Portfolios across Multiple Risk Aversions
This paper presents a continuous reinforcement learning framework for hedging arbitrary portfolios of derivatives under transaction costs and multiple risk aversion levels. The authors develop a novel risk-averse actor-critic algorithm that uses exponential utility to define a time-consistent value function, enabling simultaneous learning of optimal policies across a range of risk aversion parameters. The state representation employs a Linear Markov Representation (LMR) based on Black-Scholes Greeks (delta, gamma, vega, etc.) and portfolio-specific features, allowing the policy to generalize to unseen portfolios without retraining. The actor network outputs an adjustment to the Black-Scholes delta hedge, while the critic network outputs a risk adjustment to the book value. The algorithm is demonstrated on a Heston stochastic volatility environment with proportional transaction costs, where it learns to hedge short call options of varying strikes. Results show that the value function accurately reproduces the true utility of hedged PnL (RMSE 0.014) and provides indifference prices that extrapolate well to unseen strikes and maturities. The policy smoothly interpolates from no hedging at low risk aversion to near-full hedging at high risk aversion, outperforming both Black-Scholes delta hedging and vanilla deep hedging (which requires retraining per payoff). The framework also supports dynamic adjustment of risk aversion during an episode, enabling adaptive hedging strategies. This work significantly advances deep hedging by making it practical for real-world portfolio management with changing risk preferences and diverse instrument types.
Highlights
- 1Develops a novel risk-averse actor-critic algorithm for continuous reinforcement learning that handles multiple risk aversion levels simultaneously.
- 2Extends deep hedging to arbitrary portfolios using a Linear Markov Representation (LMR) based on Greeks and other risk metrics.
- 3Learns a single policy network that maps market state and risk aversion to hedging actions, enabling dynamic risk preference adjustment without retraining.
- 4Demonstrates that the learned value function provides indifference prices for portfolios, extrapolating well to unseen strikes and maturities.
Methods
- MRisk-averse actor-critic algorithm with exponential utility and time-consistent Bellman equation.
- MLinear Markov Representation (LMR) using Black-Scholes Greeks (delta, gamma, vega, theta, vanna, charm, vomma) for portfolio state.
- MNeural network function approximators with skip connections (actor outputs adjustment to Black-Scholes delta; critic outputs adjustment to book value).
- MTraining across multiple risk aversion levels by sampling λ uniformly in log space and including it as a feature.
Results
- RValue function achieves RMSE of 0.014 when predicting true utility of hedged PnL for random portfolios.
- RRisk-neutral limit (λ→0) recovers model prices; higher λ adds risk premium, matching monetary utility theory.
- RPolicy smoothly interpolates from zero hedge (low λ) to near-full hedge (high λ), with out-of-the-money options left unhedged due to transaction costs.
- RActor-critic deep hedging matches or outperforms vanilla deep hedging (trained per payoff) and Black-Scholes delta hedging across strikes.
- RPolicy adapts dynamically to changing risk aversion during an episode, adjusting hedge positions accordingly.
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