How to cost efficiently convert SGD to USD into following brokerages to invest in USD? SCB Tiger TD Ameritrade FSMone?

Nothing by Moomoo?

From what I remember, these are how the brokers rank in terms of cost of currency conversion (SGD to USD only):

1. Interactive Brokers (spot rate, 0.002% commission min 2 USD)

2. TD Ameritrade (DBS preferential rate**, no fees)

3. FSMOne (0.2-0.4% spread)

4. Tiger Brokers (0.2-0.4% spread)

5. SCB (0.3-0.7% spread)

6. Saxo (0.75% currency conversion fee)

**TD Ameritrade's currency conversion comes with a major disadvantage - rates are not locked in as it takes approximately 2-3 working days for them to process. This means that the rate that you see at the point of transfer may not be the same rate used to convert.

Here are the rates that I currently see at the moment (Nov 30, 2020 at 4:06PM):

• IBKR: 1.33752 (spot)

• FSMOne: 1.34094 (0.25% spread)

• Tiger: 1.3417 (0.31% spread)

• SCB: 1.34292 (0.40% spread)​​​