Which S&P 500 to buy?

A seedly writer has covered your question pretty well in the link below:

Guide to Irish-domiciled ETFs

TLDR: Buying US-listed S&P500 ETFs will incur a 30% tax on your dividends as the US does not have a tax treaty with Singapore. Instead, buy Irish-domiciled funds like CSPX on the LSE will only incur 15% tax on your dividends, which is a significant decrease esp if you're looking long-term.

Apart from choosing the best ticker, make sure you choose a broker that best suits your investment needs! Some popular brokers, like Interactive Broker, charge fees for inactivity, hence, is not the best choice for you.

Cheers!​​​

Yup, you're right. INX represents the index which is why we can't buy directly into it. We can only invest in the ETFs that track it.

If you're buying in US exchanges, some good picks would be:

• IVV/VOO

If you're buying in LSE, a good choice would be:

• CSPX

I wrote more on how I chose this ETFs in this article here!