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From: Peter C. <pca...@gm...> - 2021-09-01 07:37:52
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Hey Michael, just a few pointers that might be helpful: The QuantLib SmileSection has methods to get the smile implied cdf (via digitalOptionPrice() which is basically the cdf) and pdf (density()) https://github.com/lballabio/QuantLib/blob/master/ql/termstructures/volatility/smilesection.hpp#L71 with a simple default implementation using finite differences. In this context it's good to use an arbitrage free smile parametrization which in general is not provided by the Hagan 2002 SABR solution. One popular and modern variant of the SABR model is the normal free boundary SABR proposed by Antonov which has a semianalytic arbitrage free solution. An experimental (!) implementation can be found here https://github.com/OpenSourceRisk/Engine/blob/master/QuantExt/qle/models/normalsabr.hpp#L37 The inversion of the option price is done using an exact implied vol formula due to Peter Jaeckel https://github.com/OpenSourceRisk/Engine/blob/master/QuantExt/qle/models/exactbachelierimpliedvolatility.hpp#L33 Finally there is another approach in a discrete setting due to Carr and Madan that can be used to derive a smile implied density https://github.com/OpenSourceRisk/Engine/blob/master/QuantExt/qle/models/carrmadanarbitragecheck.hpp#L49 This implementation is restricted to the Equity / FX setting, but we'll add a variant handling IR normal and (shifted) lognormal vols in the next release of that library. Thanks Peter On Tue, 31 Aug 2021 at 16:10, Michael (DataDriven portal) < mi...@da...> wrote: > > Hi Giuseppe: > > Thanks a lot for your very insightful reply! > > I will do B-S (Breeden-Litzenberger) implied probabilities first to see if the results make sense before going to more sophisticated modelling. > > This is great, thank you! > > Michael > > On Tue, Aug 31, 2021, 3:27 AM Giuseppe Trapani <tr...@gm...> wrote: >> >> Hi Michael, >> >> apologies but I'm not getting your point: the result is valid for whatever underlying (be it interest rates / stocks / commodities) and so on, it only relies on option prices. You can compute those option prices with a model or you can get them from the market and THEN you obtain the risk-neutral density for the underlying. >> >> As for the SABR being "specific for rates" I think it's a slight misconception: the SABR model describes the dynamics of the underlying under the forward measure so you can use it with whatever underlying. It became sort of "standard" in IR markets since it's a very simple way to improve the computation of hedging ratios: when pricing vanilla derivatives in the Black-76 (or Bachelier) framework you can use it to parametrize the volatility curve and compute smile-coherent greeks. Such a framework is the most intuitive since it allows you to price the most common and liquid derivatives (Swaptions and Caps/Floors) without the need to model dependencies between the knots of the yield curve. >> >> If instead you are interested more specifically in the dynamics of the ENTIRE yield curve, you have to rely on term-structure models (for example short-rate models or maybe more involved quasi-gaussian models accounting for the skew or more modern markov-functional models). You work in a Monte-Carlo fashion like this: >> >> 1) calibrate the parameters of the model to some "information carrying derivatives" >> 2) simulate the yield curve at the horizon you need >> 3) compute whatever you are interested in (for example the 10y swap fair rate) on that curve >> 4) aggregate all the simulation results >> >> Now as for 1) term-structure models are typically low-dimensional so you cannot "calibrate" to all the IR market derivatives. A common choice is a set of coterminal swaptions or ATM caps/floors spanning the analysis horizon. Also depending on the model, 2) and 3) can have some analytic formulas / approximations so maybe you can spare yourself the whole simulation and compute directly what you need. >> >> >> >> >> Il giorno mar 31 ago 2021 alle ore 03:18 Michael (DataDriven portal) < mi...@da...> ha scritto: >>> >>> Thanks a lot! >>> >>> I see links like below Breeden-Litzenberger >>> >>> https://quant.stackexchange.com/questions/29524/breeden-litzenberger-formula-for-risk-neutral-densities >>> >>> This is very useful for B-S distributional assumptions and will work well for stocks. I am not sure if it will produce good results for interest rates which have different distributions (e.g. rates now are so low that are less likely to decrease than increase). But I will definitely give it a try. Another way to do this is to use SABR volatility model (which is specific for rates) but I am not sure if a simple solution exists to derive probabilities there. >>> >>> Thanks, >>> >>> Michael >>> >>> >>> >>> >>> >>> On Mon, Aug 30, 2021 at 11:36 AM Giuseppe Trapani <tr...@gm...> wrote: >>>> >>>> Hi Michael, >>>> >>>> to add on the previous answer, the derivative is taken with respect to the strike price of the option. >>>> >>>> It's pretty easy to derive by yourself starting from the general payoff of an option (yielding a "model free result") or from the Black-76 formula. >>>> >>>> For extra directions check online "Breeden-Litzenberger result". >>>> >>>> Giuseppe Trapani >>>> >>>> Il lun 30 ago 2021, 15:28 Michael (DataDriven portal) < mi...@da...> ha scritto: >>>>> >>>>> Yes. Thanks! If you could point me in the right direction on where I can get code for this that would be great. >>>>> >>>>> Thanks >>>>> >>>>> On Mon, Aug 30, 2021, 8:47 AM Gorazd Brumen <gor...@gm...> wrote: >>>>>> >>>>>> There is a well known formula that relates call/put prices to implied >>>>>> pricing probabilities, related to the second derivative of the >>>>>> call/put prices. You might need an implied option value >>>>>> parametrization for that. >>>>>> Regards, >>>>>> G >>>>>> >>>>>> On Sun, Aug 29, 2021 at 5:56 PM Michael (DataDriven portal) >>>>>> <mi...@da...> wrote: >>>>>> > >>>>>> > Hi All, >>>>>> > >>>>>> > I am looking for an algo to calculate option-market-implied probabilities of interest rates moves derived from the premiums of interest rate swaptions. >>>>>> > >>>>>> > E.g. market-implied probabilities from the prices of swaptions on 10-year-swap rates. What is the market-implied probability that 10Y swap rate will increase 25, 50, 75 bps, etc? >>>>>> > >>>>>> > Thanks, >>>>>> > >>>>>> > Michael >>>>>> > >>>>>> > _______________________________________________ >>>>>> > QuantLib-users mailing list >>>>>> > Qua...@li... >>>>>> > https://lists.sourceforge.net/lists/listinfo/quantlib-users >>>>> >>>>> _______________________________________________ >>>>> QuantLib-users mailing list >>>>> Qua...@li... >>>>> https://lists.sourceforge.net/lists/listinfo/quantlib-users >> >> >> >> -- >> Giuseppe Trapani > > _______________________________________________ > QuantLib-users mailing list > Qua...@li... > https://lists.sourceforge.net/lists/listinfo/quantlib-users |