ETFs are bought by many retail and institutional investors looking for low cost and highly liquid vehicles with which to buy whole indices in a single trade, and ETFs serve that noble function well. (boganassociates.com)
The first 2 buckets get 90 % of the overall weight, and are apportioned by market cap relative to the whole index. (etf.com)
Since the beginning of 2007, the banks have underperformed compared to the FTSE 100 by 32 per cent - meaning in a falling market investments in banks fell a third more than the whole index. (politics.co.uk)