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Modeling Suboptimal Bermudan Swaption Exercise Decisions

Article Quant Q&A · Author: Lucas Morin

Summary

The document considers how to represent clients’ non-optimal exercise of Bermudan swaptions, with the observation that decisions may respond to past rate movements as well as current rates. One proposed route is supervised learning: build observations pairing the product and market context with the client’s exercise decision, then fit a function that predicts the decision. Neural networks can produce exercise probabilities when trained on binary exercise outcomes, while credit scoring is offered as an analogous application of behavioral prediction.

A second answer suggests modeling exercise as optimal under a different cost function and fitting that function to historical choices. Both approaches depend on having useful decision data and suitable product and market features. The document does not present a fitted model, empirical results, or a comparison of methods, and it raises data sufficiency as a practical concern. It therefore offers possible modeling frameworks rather than evidence that either approach predicts future exercise reliably.

Key ideas

  • Supervised learning can map product characteristics and market context to observed exercise decisions.
  • Binary exercise labels can be used to estimate the probability of exercise.
  • Feature preparation should combine product and market information in a useful way.
  • A behavioral model can instead assume optimal decisions under an alternative cost function.
  • The usefulness of machine learning depends on the amount and quality of available decision data.

Tags

Full text
# Machine learning for non optimal behaviour


# Machine learning for non optimal behaviour












I was working on the pricing of complex bermudean swaption when I noticed that the exercise is often (very) subobptimal. It seems that the clients are more sensitive to past growth or drop in rates than to their value at the moment.

I am looking for a way to modelise the suboptimal behaviour and I tought about Machine learning. But I can't find any reference on suboptimal options exercice.

Do you have any broader exemple of Machine learning applied to the replication of human non optimal behaviour ?

edit: Well, I have a little background in ML (Finished Andrew Ng course on Coursera and currently going trough ESLII at a great pace). I know there is a lot of applications (see here for tons of exemple). I have played a bit with some basic algorithm and my data. I have some interesting results but also things to investigate. My question was more about quantitative finance.

## Answer by lehalle (score 1, accepted)

https://quant.stackexchange.com/a/14379

Your question is too broad, but I there is plenty of examples of uses of machine learning to mimic human behaviour. For instance deep learning has been used 25 years ago to read checks in banks, or support vector machines 15 years ago to implement artificial vision, or bayesian networks to mimic expert diagnosis.

I guess it would not be that hard to use machine learning in your case if you can implement supervised learning. It mean you should have a database of human decision $D$ associated with the product $P$ and the market context $C$. Then your goal will be to emulate the function: $$D=F(P,C)+\varepsilon.$$ Of course (as usual in machine learning), you will need to focus on pre-processing to be sure the characteristics of the product and the market context are mixed in $F$ a convenient way.

Then you will have to choose a class of model ; it is difficult to help you at such an early stage since a description of the variables and the number of data are needed. Nevertheless I gave details on Artificial Neural Networks on quant.stackexchange.

Edit:

- you should look after credit scoring. It models the way a consumer will be risky for a credit.

- Neural networks are usually good to estimate a probability. It comes from the fact that if you train them on a database with 0 or 1 as outputs (for you, will be the observation of an exercise or not), they end up with a real between 0 and 1, i.e. the probability of an exercice.

## Answer by Juan Ignacio Gil (score 1)

https://quant.stackexchange.com/a/14385

I'm not sure that machine learning would lead to any practical solutions here. Do you really have enough data for that kind of techniques?

I would suggest a different approach: assume that the exercise is optimal, but just based on a different cost function than the expected pay-off. If you can find a function that replicates well enough the past exercise decisions, maybe you can use it to predict the future ones.

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This summary was written by Stratmill's research agent from the original; it is not a copy of the source.