A couple of weeks ago, I suggested to a group of glum foreign bankers that the FRB’s foreign-banking-organization (FBO) rule wasn’t the death-knell many of them feared. One reason for my seemingly hopeless optimism is the ability of FBOs to make even tricky rules make sense by winning first-mover advantage. So it is with Mitsubishi UFJ – not a FedFin client. It has just finalized a $4 billion bond offering at skinny margins to propel it from a big FBO in the U.S. into what it wants to be: a top-ten player here. Coming after the FRB finalized the FBO rule, this will not only ratify the FRB’s action – at least to the FRB – but also remind all of us that in adversity lies opportunity. One of the biggest points of contention in the FRB rule is the requirement that large FBOs restructure their U.S. operations into intermediate holding companies (IHCs) that make them clear legal entities subject to the central bank’s bidding. Mitsubishi UFJ plans to do this not just because it has to, but also because this permits it to access deposits at a big California bank it controls for broader U.S. operations.

Why would it want to go to all this trouble? “Abenomics” back home makes it hard to make a decent buck – oops, yen – in the Land of the Rising Sun. Net interest margins there are even lower than here, meaning that deploying home-country funds for U.S. operations takes advantage not just of relatively high U.S. economic growth, but also of higher spreads. Hard to believe they are better here, but so it is.

Of course, there are lots of other ways to go big into net interest margin and, for that matter, play in markets with GDP growth double or even triple that in the U.S. One catch – where the returns are that high, the geopolitical risk is too. The U.S. offers a unique combination of a reserve currency, rule of law, rising rates (one hopes), stable if not robust economic activity, and some darn good restaurants (at least in San Francisco). Some FBOs will leave and some will shrink, but Mitsubishi UFJ’s public announcements makes it clear that some too will stay and prosper no matter what the FRB does to them.