“…The slope of ATM implied volatility depends on both the correlation and the slope of local volatility, which are therefore interpreted as skew parameters. There might be a competition between and ρ in the calibration procedures. - (ii)For pure local volatility models (i.e., ), we retrieve the results of theorem 22 in Bompis and Gobet ().
- (iii)For pure Heston models (i.e., ), we recover the expansion given in theorem 2.5 of Forde and Jacquier (). In the case of zero correlation, the approximation formula becomes, for short maturity We have obtained that an uncorrelated Heston model induces symmetric smile with respecct to the moneyness.
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