I have more than one source of trade income. Do I have to contribute to MediSave for all of them?
Your MediSave contributions are based on the annual net trade income (NTI) from all your trades. If you have a yearly NTI of more than $6,000 from all your trades, you’re required to make contributions to your MediSave Account.
You can refer to this example of how MediSave payable is computed on multiple sources of NTI.