Asymptotic Arbitrage in the Heston Model
In this paper, we introduce a new form of asymptotic arbitrage, which we call a partial asymptotic arbitrage, half-way between those of Follmer & Schachermayer (2007) [Mathematics and Financial Economics 1 (34), 213–249] and Kabanov & Kramkov (1998) [Finance and Stochastics 2, 143–172]. In the context of the Heston model, we establish a precise link between the set of equivalent martingale measures, the ergodicity of the underlying variance process and this partial asymptotic arbitrage. In contrast to Follmer & Schachermayer (2007) [Mathematics and Financial Economics 1 (34), 213–249], our result does not assume a suitable condition on the stock price process to allow for (partial) asymptotic arbitrage.