Why does it have to be expensive ? Imagine you live in Texas and already have high exposure to Texas real estate. It's reasonable to be able to construct a index fund ex texas real estate, as an example. Better tailor your investment options to your actual risks

Not from the customer front but on the operations front.

To clarify, even if you have an index, there must be enough liquidity to run a market where your index is trading. In the early days with less liquidity the company will need to pick up some of the orders. This at the end depending on the value proposition might turn out to be costly.

US REIT index Sans Texas would be less costly because you would have fewer stocks to trade

Ah ok. I see what you meant when Folio was mentioned. I was thinking something else. I was building something like that but don't have the tech capabilities so had stopped.