I think a currency can approach but never run to zero (what mathematicians call an asymptote). For example, Zimbabwe is experiencing hyperinflation at the moment, meaning that every day one US dollar buys exponentially more of the local currency and ...

Can Currency Pair Go Zero ?

Thanks for responding to my post mrmikal. I guess I knew this scenario had to be too good to be true, but I couldn't figure out why.

Using FX options to hedge carry trades