Why the same coin trades at different prices by country and exchange, why the gap does not close, how to calculate and read it, and common misreadings.
Crypto prices are set by supply and demand at each exchange. Exchanges in different countries are effectively separate markets, and when buyers crowd into one, only that market's price rises. Normally buying where it is cheap and selling where it is dear would narrow the gap, but where that movement is not free, the gap remains.
The coins themselves move across borders quickly, but the money paying for them does not. Moving currency involves procedures and limits, and bank and exchange checks take time. If the price moves during that window, the expected difference disappears. A gap existing and a gap being capturable are different things.
A widening gap is read as local buying pressure running ahead of overseas. It is therefore often used as a reference for how heated a market has become. A local price below the global one is sometimes read as local participants having stepped back first. These remain interpretations and do not indicate future direction.
Calculating the gap needs a local price, an overseas price and an exchange rate. All three move, so the figure for the same moment differs depending on which rate is used. Numbers that disagree between sources usually differ in their basis.
Trading on the gap ties directly into cross-border transfer rules, currency regulations and taxation. Rules differ by country and change over time. This piece explains why the gap appears and persists, and stops short of how to act on it. Anyone considering it should check the applicable rules first.
The formula is simple: convert the foreign exchange's dollar price to won using the won–dollar rate, then find how many percent higher the Korean exchange price is. However, foreign prices are often quoted in a stablecoin such as USDT rather than actual dollars, so the small gap between the stablecoin and the dollar creeps into the result. If the domestic and foreign prices aren't taken at the same moment, price movement in between looks like a premium. The figure also changes depending on whether you use a bank's posted rate or a live market rate. When comparing figures, first check that the bases match.
Even at the same moment, the size of the gap varies from coin to coin. Coins traded heavily only on Korean exchanges are more exposed to domestic demand, and their gap can widen sharply. Coins traded far more abroad are pulled more strongly toward the foreign price. And if deposits and withdrawals for a coin are temporarily suspended on a Korean exchange, even cross-border movement is cut off and the gap can become abnormally large — a big number with no way to act on it. That's why, as an indicator, the figure based on major high-volume coins is a steadier reference.
A few misconceptions are worth clearing up. A large gap is no guarantee that it will shrink soon; it can stay high for quite a while. A reverse premium doesn't mean buying in Korea is advantageous either — if the foreign price itself falls, you lose regardless of the gap. And buying domestically when the Korean price is higher means paying that premium too, so as the gap closes, the domestic price can fall further than the foreign one. This guide explains the structure and does not recommend trading or arbitrage.
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