Need a bit help in understanding how to calculate Bank Nifty % change from its underlying companies


The screenshot contains Bank Nifty & its companies return on 21 Jan 2022.

Now,

Bank Nifty decrease by -0.73%

How can I get the same percentage change from it’s underlying companies?

If I sum the Return attribution column, I only get -0.46% change. So why Bank Nifty decreased by -0.73%?

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Not an expert and not sure this will answer your query, however, just stating it

Please have a look at this site from money control. It has a field called contribution. When I add the contribution, I get the total of -276.54. This is exactly -0.73% as of Jan 21.

How exactly the contribution is calculated, I tried to search the net to find out but could not. Hope some experts will give a reply.

https://www.moneycontrol.com/stocks/marketstats/indcontrib.php?optex=NSE&opttopic=indcontrib&index=23

There is another post similar to this and this too remain inconclusive…

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Contribution of each component of an index is proportional to its market cap.

I tried to calculate Nifty 50 & Nifty MidCap Select Index % change, and calculated them almost accurately. Why only Bank Nifty calculations wont match up.

Can someone please tag a knowledgeable person here. Really not able to figure it out.

Can you share where you’re reading this return attribution from?

The percentage contribution is calculated based on NSE’s index calculation methodology.

You can find it here: Index Calculation

Return attribution is calculated by multiplying the “stock 1D change” by it’s weight.