We work differently in South Africa. Our ETFs always have a market maker, a kind of a robot that will always buy or sell to ensure liquidity. They work at a small spread, maybe 0.2%, but it does keep the ETF very closely matched to the value of the underlying shares. Without it I would never be able to buy my favourite ETFs, as we just don't have that many traders in them. Sadly that means I can't profit on that discrepancy like I know a few people have done.