Book Image

Python for Finance

By : Yuxing Yan
Book Image

Python for Finance

By: Yuxing Yan

Overview of this book

Table of Contents (20 chapters)
Python for Finance
About the Author
About the Reviewers

Constructing an efficient frontier

In finance, constructing an efficient frontier is always a challenging job. This is especially true with real-world data. In this section, we discuss the estimation of a variance-covariance matrix and its optimization, finding an optimal portfolio, and constructing an efficient frontier with stock data downloaded from Yahoo! Finance.

Estimating a variance-covariance matrix

When a return matrix is given, we could estimate its variance-covariance matrix. For a given set of weights, we could further estimate the portfolio variance. The formulae to estimate the variance and standard deviation for returns from a single stock are given as follows:

Here, Ri is the stock return for period i, is their mean, and n is the number of the observations. For an n-stock portfolio, we have the following formulae:

The variance of a two-stock portfolio is given as follows:

Here, is the covariance between stocks 1 and 2, is the correlation coefficient between stocks 1 and 2....