Savvy DIY investors have long used a technique called “Norbert’s gambit” to sidestep these steep currency conversion costs. The name comes from Norbert Schlenker, an investment advisor in B.C. who was the first to popularize it.

Here’s an analogy that might help you understand the idea. Imagine you live in Windsor, Ontario, and you want to exchange $100 Canadian, which at today’s spot rate is worth $95 US. But your local bank offers you only $93 US, because it will keep the other $2 as its profit. So you come up with a bright idea: you go to your local Walmart and buy an item for $100. Then you drive across the border into Detroit, where there is another Walmart that sells the same items for the equivalent amount of US dollars. You take your newly purchased item to the customer service desk and return it for a refund of $95 US. Now you’ve received a fair exchange on your money and sidestepped the bank’s $2 fee.