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Stability of calibration procedures: fractals in the Black-Scholes model |
Yiran Cui 1, Sebastian Del Baño Rollin 3, Guido Germano 1,2 |
1. University College London (UCL), Gower Street, London WC1E6BT, United Kingdom |
Abstract |
Usually, in the Black-Scholes pricing theory the volatility is a positive real parameter. Here we explore what happens if it is allowed to be a complex number. The function for pricing a European option with a complex volatility has essential singularities at zero and infinity. The singularity at zero reflects the put- call parity. Solving for the implied volatility that reproduces a given market price yields not only a real root, but also infinitely many complex roots in a neighbourhood of the origin. The Newton-Raphson calculation of the complex implied volatility has a chaotic nature described by fractals. |
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Presentation: Oral at Econophysics Colloquium 2017, Symposium A, by Guido GermanoSee On-line Journal of Econophysics Colloquium 2017 Submitted: 2017-03-16 15:59 Revised: 2017-03-16 15:59 |