Comment by hiAndrewQuinn

I'm using 'index fund' broadly to refer to the cost structure - very low management fees, very "dumb" wide market tracking. Plenty of these already exist in the EU, for EU citizens, you are correct.

But yes, they are taxed differently. A US-domiciled fund is much easier for US expats to invest in without risking losing over 100% of their return (I am not exaggerating), but only if you can actually find one which will accept money from you while resident in the EU. None do, to my knowledge, An EU-domiciled fund would probably be classed as a PFIC and have to fill out reams of paperwork to avoid messing up people's taxes. One that US expats love is possible in theory, but no one has brought one to market yet because it requires dealing with a lot of US taxation errata.