Stock Calculator

Trading International Stocks: Fees, Currencies, and Hidden Costs

by Stock Calculator published

Buying a foreign stock is buying two things: the share, and the currency it’s priced in. Most of the surprises in international trading come from forgetting the second purchase — and from a fee stack that is longer, and better hidden, than the domestic one.

The fee stack, layer by layer

A domestic trade has a commission and a spread. An international trade can add:

  • FX conversion, the big one. Brokers convert at an exchange rate marked up from the interbank rate — commonly somewhere between 0.1% and 1%+ retail. It’s charged going in and coming out, usually without appearing as a line item. On a round trip, a 0.5% FX markup each way costs more than most commissions ever did.
  • Local transaction taxes. Several markets levy duties on purchases — the UK’s stamp duty reserve tax (0.5%) and Hong Kong’s stamp duty (0.1%) are the familiar examples — paid on top of whatever your broker charges.
  • Custody, ADR, and dividend-handling fees. Depositary receipts commonly pass through small per-share annual fees, and foreign dividends may arrive minus a withholding-tax slice whose partial recovery depends on treaties and paperwork — jurisdiction-specific territory this site deliberately doesn’t calculate.
  • Wider spreads and thinner hours. Trading a foreign name through a secondary listing or outside its home hours often means paying a wider bid-ask spread — a cost that never shows on any statement.

None of these is scandalous alone. Stacked, they raise the break-even price of an international position noticeably: a 0.5% FX markup each way plus a 0.5% duty plus commissions can mean the position must rise ~1.5–2% before the first cent of profit — the same treadmill-tilt arithmetic as domestic trading costs, with extra rollers.

The currency question

The share can rise while the position falls. If you buy a Tokyo-listed stock and the yen weakens 10% against your home currency, a flat stock price is a losing position in your money. Currency exposure isn’t a defect — sometimes it’s half the reason for the trade — but it deserves to be counted deliberately, not discovered at sale.

A counting convention that keeps the math honest: run each position in its trading currency. This is exactly why the position calculator has a display-currency selector that formats and never converts — enter a Hong Kong position in HK$ with its HK$ fees and stamp duty, read HK$ results (the selector renders HK$, €, ¥, CN¥, £, even ₿ with each currency’s own decimal conventions), and treat the FX leg as its own position with its own P/L. Mixing currencies inside one calculation with a hand-waved rate produces numbers that are precisely wrong; separating the legs produces two numbers that are each exactly right.

A worked example, both legs

Buy 1,000 shares at HK$50 with a 0.25% commission and 0.1% stamp duty: HK$50,175 invested. The stock climbs to HK$55 and you sell with the same commission — realized profit ≈ HK$4,687 (+9.3%), computable to the cent in the calculator with a 0.35% buy-side and 0.25% sell-side percentage fee.

Now the FX leg. If you converted from dollars at the start and back at the end, and the HK dollar moved 1% against you while the markups took 0.5% each way, roughly 2% of the position — about HK$1,000 here, a fifth of the stock-picking profit — belonged to the currency, not the stock. Whether that ratio is acceptable is a judgment; that it should be visible before the trade is just arithmetic hygiene. Fees you can see are fees you can count — and counting them is what this site is for.