Depends on the prospectus, most I've looked at that do this sort of thing says they will hold something in every sector to match the returns, but are nonspecifi

Depends on the prospectus, most I've looked at that do this sort of thing says they will hold something in every sector to match the returns, but are nonspecific as to the exact composition of how much they aim to hold of each sector to match the overall returns(talking about total-market/return funds btw, S&P 500 was a bad example since a lot of REITs are not in the 500 anyway).