Reinforcement Learning for Speculative Trading under Exploratory Framework
Authors: Yun Zhao, Alex S. L. Tse, Harry Zheng
Organizations: Department of Mathematics, Imperial College, London SW7 2AZ, UK. · Department of Mathematics, University College London, London WC1H 0AY, UK.
We study a speculative trading problem within the exploratory reinforcement learning (RL) framework of Wang et al. [2020]. The problem is formulated as a sequential optimal stopping problem over entry and exit times under general utility function and price process. We first consider a relaxed version of the problem in which the stopping times are modeled by the jump times of Cox processes driven by bounded, non-randomized intensity controls. Under the exploratory formulation, the agent's randomized control is characterized via the probability measure over the jump intensities, and their objective function is regularized by Shannon's differential entropy. This yields a system of the exploratory HJB equations and Gibbs distributions in closed-form as the optimal policy. Error estimates and convergence of the RL objective to the value function of the original problem are established. Finally, an RL algorithm is designed, and its implementation is showcased in a pairs-trading application.
Figures & tables
Figure 1: Value function V0(p) under different (M,η)
Figure 2: Value function V1(p,b) under different (M,η)
Figure 3: Optimal entry density πα,∗(λ;p) when η is high
Figure 4: Optimal entry density πα,∗(λ;p) when η is small
Figure 5: Optimal exit density πβ,∗(λ;p,b) with M=50 , η=10−5
Figure 6: Free boundary of p as a function of b with M=50 , η=10−5
Figure 7: Value function V0(p) under different θ and σ
Figure 8: Comparison of value functions V0(p) and V1(p,b) between policy iteration and HJB with M=50,η=10−5
Department of Mathematics, University of Southern California, Los Angeles, CA 90089 · Department of Industrial Engineering and Operations Research, Columbia University, New York, NY 10027