CDP is to keep all your SGX stocks regardless of what brokerage you are using as long is direct brokerage and not nominee account. CDS is the equivalent for Malaysia. How about US stocks?

Interesting question! I went to search and it seemed like someone had the same question as you. Here's the answer to your question: https://seedly.sg/posts/do-i-need-a-cdp-account...

If I'm not wrong, you need to specifically transfer your SG stocks to CDP. If not it is held in your broker's custodian account.

All other stocks are held in custodian accounts.