You begin by collecting historical stock price data for the company XOM. Our purpose is to compare the returns of this companys stock to how stock prices are doing in the market overall. S&P500 (ticker: ^GSPC) is our benchmark for overall stock market performance. Historical prices of your company and S&P 500 are available in http://finance.yahoo.com website. You use monthly data beginning 1^st Jan 2018 and ending 31^st December 2020. Now bring these information into an Excel file.

Go to finance.yahoo.com. Type your company ticker symbol in the search box at the top of the webpage. Click on Historical Data link. Change the Time Period (1-Jan-2018 to 31-Dec-2020) and Frequency (Monthly). Click on Apply, and then click on Download Data. Repeat these steps for ^GSPC (S&P500). Create an excel file (do not use the .csv file) with the months, the adjusted close prices for your company and S&P500. You need the recent months information at the top (use sort newest to oldest).

Calculate returns in Excel

Now we will calculate monthly returns (in percentage) using Adjusted close.

Use the following formula: Monthly Return = (Price next month Price this month)/ Price this month or

For example: January 2018 return = (Price for February 2018 Price for January 2018)/ Price for January 2018

Calculate the returns for both your stock and S&P500. Percentage returns gives us an ability to compare different investments during a particular time period. This allows us to compare different investments relative to the amount of money we have invested in the stock.