At the end of June, the Federal Reserve extended its dollar swap lines to the European Central Bank, the Bank of England, the Swiss National Bank and the Bank of Canada. During the panic, up to fourteen central banks were using these lines. Simply put: The dollar is the world’s reserve currency and so the Fed is the world’s lender of last resort.
The panic is over now. So what about the carry trade then? Since interest rates are as low as they can go in the U.S., it makes sense for institutions, domestic and foreign, to load up on USD debt and buy investments wherever the return is highest.
The swap lines were set up to deal with the lack of dollar liquidity that foreign banks like UBS (UBS) or Royal Bank of Scotland (RBS) have had. They borrowed dollars short-term in the interbank market, making them subject to rollover risk in a foreign currency from lending long and borrowing short in USD.
Higher interest rates would end the appeal of the carry trade. I am skeptical that the Fed will raise rates anytime soon. You would need a lot more inflation for that to happen. You do have The St. Louis Fed’s James Bullard of “Seven Faces of The Peril” fame out trying to anchor the discussion around headline inflation. However, the consensus at the Fed is going with core inflation -- and right now core inflation is not going into the stratosphere. The same is true for the U.K. by the way, where inflation is well above the central bank’s target. Note that despite Chinese hikes, Chinese real rates are negative, so it's clear that the Fed and the BoE are not the only ones on easy street.
If inflation does rise, it will probably be because of demand-destroying commodity price inflation and bubblicious asset prices. The key thing to watch, that could force the Fed's hand, is owner's equivalent rent. If that rises too much, you would see a reaction by the Fed as it is a sizable percentage of the core.
Bottom line: the Fed is stuck at permanent zero and that means the carry trade is on. If we did have another panic, those swap lines would be handy because the Fed would again become the global lender of last resort.