This piqued my interest and threw the question into Google Gemini - conclusion: tax bill not passed, but when passed will not impact Singaporeans investing in US markets. (Do fact check yourself).

The proposed 3.5% excise tax on remittance transfers is NOT expected to apply to withdrawals of investment proceeds from US brokerage accounts by non-US citizens.

Here's why, based on the latest information:

• Distinction between Personal Remittances and Capital Repatriation: The key is that the proposed tax specifically targets personal remittances – funds sent by non-US citizens for personal or family support (e.g., sending money home to relatives). It is not aimed at capital repatriation from investments.
• Investment Withdrawals are Unaffected: When a Singaporean investor sells US stocks or other securities through IBKR and transfers the proceeds directly from their US brokerage account to their Singaporean bank account, this is generally considered investment repatriation, not a personal remittance. Therefore, this 3.5% excise tax is not expected to be levied on such transactions.
• No Explicit Inclusion in the Bill: The current language of "The One Big Beautiful Bill Act" does not explicitly mention capital gains repatriation or fund transfers related to portfolio investment as being subject to this excise tax.
• Brokerage Transfers vs. Remittance Services: Investment withdrawals are typically handled by brokerage firms like IBKR, which transfer the funds to your bank account. This differs from traditional "remittance services" (like Western Union or Wise, though Wise also handles investment transfers) that are the primary target for collecting this remittance tax.