Python for Finance: Analyze Big Financial Data

(Elle) #1

Chapter 18. Portfolio Valuation


Price is what you pay. Value is what you get.

— Warren Buffet

By now, the whole approach for building the DX derivatives analytics library — and its


associated benefits — should be rather clear. By strictly relying on Monte Carlo


simulation as the only numerical method, we accomplish an almost complete


modularization of the analytics library:


Discounting


The relevant risk-neutral discounting is taken care of by an instance of the


constant_short_rate class.


Relevant data


Relevant data, parameters, and other input are stored in (several) instances of the


market_environment class.


Simulation objects


Relevant risk factors (underlyings) are modeled as instances of one of three


simulation classes:


geometric_brownian_motion

jump_diffusion

square_root_diffusion

Valuation objects


Options and derivatives to be valued are modeled as instances of one of two


valuation classes:


valuation_mcs_european

valuation_mcs_american

One last step is missing: the valuation of possibly complex portfolios of options and


derivatives. To this end, we require the following:


Nonredundancy


Every risk factor (underlying) is modeled only once and potentially used by multiple


valuation objects.


Correlations


Correlations between risk factors have to be accounted for.


Positions


An options position, for example, can consist of certain multiples of an options


contract.

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