“…It has been a standard practice for practitioners to obtain the option price and delta from the asymptotic approximation of implied volatility (Hagan et al, 2002), but the approximation loses accuracy and allows arbitrage as the variance of volatility becomes large. Despite numerous attempts to improve implied volatility approximation (Ob lój, 2007;Paulot, 2015;Lorig et al, 2017;Yang et al, 2017;Choi and Wu, 2021a), it does not seem possible to obtain an approximation accurate for all parameter ranges. To date, there are several full-scale methods for pricing the SABR model: Monte-Carlo simulations (Chen et al, 2012;Leitao et al, 2017a,b;Cai et al, 2017;Choi et al, 2019;Cui et al, 2021), finite difference methods (Park, 2014;von Sydow et al, 2019), and continuous-time Markov chains (Cui et al, 2018).…”