August 14, 2015 Leave a comment
When using Datastream the datatype RI (return index) includes the re-investment of dividends. The total return can be calculated from the change in the return index over the chosen time period. The basic fomula is:
Retit = ( RIit – RIit-1 ) / RIit-1 (multiply by 100 for percentage return)
The percentage return can be calculated using a Datastream formula.
For example, PCH#( X(RI), 1M )
- percentage change (PCH#) of
- the series return index (X(RI))
- over 1 month (1M) (you can have 1D for one day, 1Y for one year etc.)
This gets the return for a company when X is an equity series, for an index when X is a index series, and for a group of companies when X is a list.
If you want the percentage change in price, that is without re-investment of dividends, you can use P rather than RI,
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