Basic information on financial databases: cook books, tips and tricks & economic news

This blog contains schematic easy to grasp - hands on - help in performing searches in economic databases, making work sets and making them inter-exchangeable between the databases.

* Disclaimer. I am not a finance professional. Most posts are the result of personal findings.

All presented images are scaled and can be enlarged to original size (click the picture).

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BETAs in Datastream

Beta's are used to measure the volatility of a share.

Static search is pretty easy, as the pic illustrates


Only the the latest calculated BETA can be retrieved from Datastream as a number for active equities.
Static Request is needed.

But what is a beta?

Betas compare the movement of a stock against the market. Over a period it expresses the relative movement of the price against the market.

Calculation method:

The beta factor is derived by performing a least squares regression between adjusted prices of the stock and the corresponding Datastream market index.
The Datastream beta factor is calculated using stock prices and market indices as the only variables.
Calculation is explained here (click link)
Calculations in Excel:


The following site explains how to calculate your own Betas

First step is : downloading prices for stock (P) and benchmark index (Pi) (the index it is traded)

2nd step: Calculate % returns: =((Cell2-Cell1)/(Cell1)*100
(see image above)

Step 3, Beta:
(1 option) Beta = Covar(rs - rm)/ var(rm)
rs = return stock and rm is return market

(2 option) (excel’s slope function) Beta = SLOPE(range of % change of equity, range of % change of index)   (see image above for equity)

Historic BETAs can be calculated through the following formula:

X = market index (e.g. TOTMKUK or FTALLSH) Y = equity (e.g. MKS)

Condition for your research is that the BETAs you calculated are from equities that are part of the same market Index, or else they can't be compared.

Or you can use the menu (ready made formula's) here

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