Comparing Company Share Price Performance
Datastream is useful to be able to search for multiple companies (Series) and datatypes, in terms of quantitative data.
For example, Tesco PLC, J Sainsbury PLC and Marks & Spencer Group PLC are UK supermaket groups, each within the FTSE100 Price Index. One measure of company performance is Share Price. This quantitative data can be represented in chart form.
Data Category is the starting point. For company related data, this would be ‘Equities’.
For Analysis, this would be ‘Time Series Data’.
The Series can be identified by using the Navigator function, activated by clicking on the ‘Find Series’ button. The code displayed in the Navigator search, when selected, gets copied into the search screen. For example, TSCO for Tesco PLC.
The Datatype, for Share Price, searchable via the Navigator (Datatypes button) is ‘Price (Adjusted – Default)’, represented by the code: ‘P’.
Time Period can be selected from set date ranges, such as ‘-10Y’, which represents the last 10 years. Alternatively, a specific date range can be entered by clicking on the ‘Time Period’ button, giving the option to enter a Start and End date using the format: DD/MM/YYYY.
The frequency of data can be selected by clicking on the Settings button. This allows choices of ‘Daily, Weekly, Monthly, Quarterly and Yearly’, with a default of ‘Daily’. Daily is normally used for Share Price data.
Finally, click on the Run Now! button to execute the search.
The results of this search for Tesco PLC Share Price data, in Datastream 5.1, gives the following output:
It is then possible to add this data into a chart view, by selecting Multiple Series/Flexible Chart, then Comparison Line Chart then Rebased.
By clicking on the plus [ + ] symbol, the Series is copied into the chart summary box on the left of the screen.
Go back to ‘Time Series Data’ Analysis option, run the search for the next company’s Share Price and repeat the process, to include all those required in the chart summary box:
Execute the search by clicking on the ‘Run Now!‘ button at the top right of the screen.
By virtue of specifying ‘Rebased’, this represents the different series as an index, beginning at 100. This allows a relative view of performance. Hence, a movement from 100 to 95 represents a 5 per cent decrease in the share price of a company. All three companies are showing a value of about 40 (as at 24/3/2017), indicating they have lost approximately 60 per cent of their value, as expressed by Share Price, over the last 10 years.
Price Index Comparison
By comparing a number of companies within a particular Price Index, it is possible to get an appreciation of how the companies have performed relative to the whole index. Tesco PLC, J Sainsbury PLC and Marks & Spencer Group PLC are all part of the FTSE100 Price Index.
Using the Analysis option ‘Comparison Line Chart – Rebased to First’ gives a scale relating to the first series (FTSE100). To do this, run a search for the FTSE100 data first and subsequently the companies also part of the index. Changes to the search above include:
Data Category: ‘Equity Indices’, Datatype: ‘Price Index’ and run the search for data.
Next, change back to the settings for Companies (Data Category: Equities, Datatype: Price (Adjusted Default), run the searches for data and add to the chart summary box [ + ].
Next, click on the ‘Run Now’ button to execute the search.
This chart gives a clear graphical representation of the relative performance of company Share Prices and the FTSE100 Price Index. The competition from low cost retailers such as Aldi and Lidl is a factor in the poor recent performance of Tesco PLC and J Sainsbury PLC in particular, reflected in the above chart.
Datastream is available to current students and staff of The University of Manchester.