# Investing and personal finance — writing and calculating

Mathieu Bouville, PhD

## Writing

I am the author of the book "Votre argent mérite de vous rapporter plus" as well as of articles on investing and personal finance for a broad audience.

## Calculating

When my knowledge of investing meets my skills and experience in mathematical modeling and numerical simulations, I do things like modeling stock–bond portfolios (github.com/m-bouville/investing-by-numbers).

I am also designing and implementing a personal finance simulation tool which calculates the long-term evolution of your wealth based on those of your income and expenses. The difference between the two is invested in a stock–bond portfolio and the possible evolution of your wealth is calculated with Monte Carlo simulations to then be plotted, as in the figure to the right.

## Both

I am working on quantifying objectively after how many years an equity investment starts behaving differently, i.e. when 'the long term kicks in'. Indeed the claim that the stock market is an investment for the long term is as common as empirical, robust thresholds for it are rare. 'Recommendations' tend to look something like 'the time horizon for stock investments should be no less than *x*', where *x* can be 5 years, 10 years, any number. Read the article "When investing in stocks, the long term starts at three decades" (any input or show of interest is welcome).

© Mathieu Bouville, March 2016