I’m thinking of starting to invest $1.5k in STI ETF and $500 in S&P next month onwards using DCA. Is it wise considering that it’s bearish for STI ETF and yet all time high for S&P ?

How do you intend to buy into the S&P through a DCA method? I'll assume you are referring the S27 SGX counter? There is no automatic way of buying into S27 and the minimum share lot is 10, which works out to be US$2650~ per transaction based on today's prices.

If you are buying to SPY, you are looking at perhaps 1 share a month based on your $500 contribution. Which doesn't make sense, as the brokerage fees will be quite high.

Unless you are thinking of buying into the Infinity S&P500 fund issued by LionGlobal, in which case I'll suggest you stay far away. The fees are rather high which will eat a big chunk of your paper gains over time.

Nobody knows where the market is going, that's why a DCA strategy is good because it gives you a plan to buy consistently regardless of whether the market is up or down. Personally, I would overweight more on the global indexes rather than STI ETF.

If you are doing dca, you should not time the market as you will be consistently buying every month and in the long term, it will average out.

Diversification seems a good thing,

look what happened the last 10 years with STI versus S&P500 (chart)

more on my thinking

https://seedly.sg/questions/what-is-your-general-investing-philosophy-strategy​​​

Since you are using DCA, it does not really matters. However, if you are using lump sum, it makes a lot of difference and it is advisable to go into the market after a correction.

It doesn't matter since you're using the dollar cost averaging method. Just note that this is a long term one, meaning you'll need quite a few years before seeing good results

If you are using DCA, then time in the market is better than timing the market! Your costs will average out in the long run anyway!

If you're into DCA, it's works better when it's in bearish. As you purchase more units when it's bearish. When it's at the bottom and have analysis that's it's going to be bullish put a lump sum.

if you are using DCA, then the time you invest does not really matter. DCA is supposed to remove the aspect of market timing and keep you invested whether at market top or bottom.

The longer you hold the better