The papers (Forde and Jacquier in Finance Stoch. 15:755–780, <CitationRef CitationID="CR1">2011</CitationRef>; Forde et al. in Finance Stoch. 15:781–784, <CitationRef CitationID="CR2">2011</CitationRef>) study large-time behaviour of the price process in the Heston model. This note corrects typos in Forde and Jacquier (Finance Stoch. 15:755–780, <CitationRef CitationID="CR1">2011</CitationRef>), Forde et al. (Finance...</citationref></citationref></citationref>

The purpose of this paper is to improve and discuss the asymptotic formula of the implied volatility (when maturity goes to infinity) given in [3]. Indeed, we are here able to provide more accurate at-the-money asymptotics. Such analytic formulas are useful for calibration.