CU6 - ASX Charts, page-1428

Index funds work by buying and selling stock in their fund to the public that want to own the index - for listed index funds like IOZ and STW they use market makers to mark the prices to approximate the index for people who are buying or selling those listed index funds. If the index funds hedged their positions in the stocks in the ASX200 and those stocks all went up then the fund is going to go broke - or they'll be marking the price of their own index fund stock at prices that no longer reflect the index so no one would buy their fund as they aren't doing what they say they will do(and then they'll go broke). They don't make their money from the stocks in the index going up or down, they make their money by charging fees to the people who own their index fund stock. Something like CU6 will be such a tiny part of their fund it will make next to no difference anyway, not that they care whether it goes up or down as that's not their business