Market capitalisation indices look much the same

Market capitalisation indices have been used for benchmarking the performance of equity fund managers for decades. There are a number of index providers we can chose from. However, the difference in the performance of market capitalisation-weighted indices tends to be tiny, as long as they apply to the same investment universe, e.g. country or sector. The market capitalisation of a company is a precise and known metric, so the weight of a stock in a benchmark index derived from its stock market capitalisation is comparable from one index provider to another.