They run ETFs, they simply invest other people's money weighted...

They run ETFs, they simply invest other people's money weighted by the index. The fund doesn't aim to make money investing, they make their money charging fees to the people who invest. It's like an ETF such as IOZ which is an ASX200 ETF, they simply hold the stocks within the ASX200 which then makes the fund returns approximate the index. The people who buy and sell the ETF make or lose based on the index moves, the fund makes their money charging fees