Tree on Paths Method for Efficient Securities Valuation

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Solution Overview

Problem

Current methods for valuing American-style and Bermudan-style callable debt securities are computationally expensive due to high computational costs associated with Monte-Carlo simulations, especially when dealing with multi-factor models, making it difficult to accurately determine early exercise decisions and manage portfolio risk effectively.

Innovation Solution

The tree on paths method uses Monte Carlo simulations to generate paths and recombines them into a computationally efficient recombining interest rate tree, allowing for easier and more efficient valuation of various types of securities, including American-style, European-style, and Bermudan-style, by approximating the distribution of process state variables and calculating probabilities to match the stochastic process's conditional mean and variance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Monte-Carlo simulation is used to value American-style and Bermudan-style callable debt securities, then the ability to handle complex payoff functions and path-dependent securities is improved, but the computational cost increases linearly with the number of underlying factors

Engineering Contradiction:
Improveability to handle complex payoff functionsVSAvoidcomputational cost
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the continuous Monte-Carlo simulation paths into discrete time steps and recombines them into a tree structure. This segmentation allows the complex valuation problem to be broken down into manageable discrete states that can be recombined efficiently, reducing computational cost while maintaining the ability to handle complex payoff functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a recombining tree structure that copies and reuses simulation paths across different nodes. Instead of running separate simulations for each possible path, the method copies existing paths and recombines them, significantly reducing the number of computations needed while preserving the statistical properties of the original Monte-Carlo simulation.

Inventive Principle:
Principle #26Copying

2Measurement precision

If a large number of Monte-Carlo simulation runs are performed to achieve desired precision, then measurement precision is improved, but the computational cost and time required increase

Engineering Contradiction:
Improvevaluation precisionVSAvoidcomputational efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent merges multiple simulation paths by recombining them into a tree structure where common paths are consolidated. This merging reduces the total number of computations needed to achieve the same precision, as identical or similar paths are computed once and reused across multiple nodes in the tree.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent performs preliminary actions by pre-computing and storing simulation paths that can be reused. By generating and saving paths in advance, the method avoids redundant computations during the valuation process, improving computational efficiency while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If standard Monte-Carlo simulation is used for American-style derivatives, then the ability to model term structure is improved, but the difficulty of detecting and measuring optimal early exercise decisions increases

Engineering Contradiction:
Improveterm structure modeling capabilityVSAvoidearly exercise decision detection
Core Design Contradiction:
Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent adds a temporal dimension by organizing simulation paths into a tree structure with discrete time steps. This dimensional transformation allows the method to track and evaluate early exercise decisions at each node in the tree, making it possible to detect optimal exercise timing by comparing values across different time dimensions while maintaining term structure modeling capabilities.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS7818244B1Tree on paths method and system for modeling securities
Publication Date: 2010.10.19 FANNIE MAE
  • US7818244B1 patent drawing
  • US7818244B1 patent drawing
  • US7818244B1 patent drawing

AI summary

A system for implementing a tree on paths method for generating a recombining interest rate tree from previously generated paths. The inventive method is a tree on paths method whereby a tree is created from previously generated paths. The tree on paths method uses Monte Carlo simulations to generate paths and uses a recombining algorithm to obtain a computationally efficient tree from the generated paths.