How much is the optimal amount to invest into a single stock? $5k? $10k? How do I determine how much I should be putting into a single stock?

Hi, as Dan L have mentioned, the best way is to optimise the sales charge and commision to the trading platform.

For myself, I'm using DBS Vickers Cash Upfront. (Min sales charge $10). Thus average about 8k investment per trade will be optimal.

The stocks will be held in CDP, central depository. Which means you can sell thru other brokers / platform

I sell thru FSMone as the min sales charge is also $10. For DBS Vickers, sell min is $25.

Assuming a commission rate of 0.28% and minimum of $25- you'll likely want to transact $8,928 to meet the minumum brokerage

e.g. Singapore Stocks

$5,000 * 0.28% = $14, but you'll still pay $25

$10,000 * 0.28 = $28​​​