[raverbashing]

They don't need to sell a billion dollars, they need to move a billion dollars

And yes, they might increase their fees when they get bigger, still, if it's smaller than what the banks charge, it's a win

(However, since money movements are not balanced they still need to "move back" some of it so they can settle their accounts - but I guess they already have some bulk currency buyng/selling bank to do that)

[charlesdm]

Not sure about that. Perhaps if they're super convenient to use. But if I'm going to put in the time to set up a system to reduce fees on FX conversions, I want to be sure I'm getting (close to) the best rate possible.

If they start charging 1% tomorrow, up from 0.5%, I'm pretty sure I would reconsider if I were using them (and I have used them in the past, in the early days -- they're great).

But I started routing currency conversions through an account at my broker (Interactive Brokers), and I'm currently getting market rate + 0.2%. These 0.3%s add up fast if you're converting meaningful amounts of money and in comparison Transferwise seems expensive again. But of course it's still a long way from the 2.5-5% banks are charging.