winpieTaiwan-focused

US Broker vs Sub-BrokerageTW-specific

Taiwan retail investors have two main ways to buy US ETFs: open an account at a US broker (e.g., Firstrade, Interactive Brokers, Charles Schwab) or use a Taiwan sub-brokerage (複委託). The cost structures differ dramatically — this tool finds your break-even trade size.

Inputs

Overseas broker (e.g. IBKR, Schwab) parameters

Includes Taiwan wire fee (about NT$750, ~US$25) plus FX spread.

Sub-brokerage (via Taiwan broker) parameters

Rates vary by broker; adjust to match your actual account.

Results
10-year cumulative cost difference
Roughly equal
Overseas brokerSub-brokerage
Cost per tradeUS$ 25US$ 25(minimum applied)
Cost per yearUS$ 100US$ 100
Cumulative costUS$ 1,000US$ 1,000
Break-even point
At a trade size of US$ 8,333.33 the two costs are equal (sub-brokerage rate 0.3% × trade size = wire cost).
  • Trade > US$ 8,333.33: overseas broker is cheaper.
  • Trade < US$ 8,333.33 (if above sub-brokerage minimum): sub-brokerage is cheaper.

Not included: overseas broker inactivity fees (usually none), US ETF expense ratios (same either way), dividend withholding tax (~30% either way), and US estate-tax risk (relevant to overseas brokers). Numbers compare costs only and do not prescribe a choice; consider your own risk tolerance and convenience.

Cost structure

  • US broker: usually 0% commission on US ETFs + US$25 per wire transfer + exchange rate spread
  • Sub-brokerage: 0.15–1% commission, US$15–35 minimum fee, no wire but internal FX spread 0.2–0.5%

Rule of thumb: large trades (US$5K+) tilt toward US broker. Small recurring trades (under US$2K) tilt toward sub-brokerage if they offer dollar-cost-averaging discounts.

Also consider estate tax risk: US broker accounts over US$60K are subject to US estate tax if the account holder dies — a frequently overlooked concern for Taiwan foreign nationals.

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