Noah Smith
22 Oct 2015
Why are interest rates so low? For macroeconomists, this is one of the Big Questions in the world today.
Government bond rates are at or near record lows. So are corporate bond rates, including junk bonds. Even the cost of equity capital is at or near an all-time low for most businesses. Whether you're a government, a big corporation or a tiny start-up, it has never been cheaper to obtain capital.
Interest rates have been in decline since the early 1980s. For a while, that looked like a simple regression to the mean. The early 1980s saw central banks tighten a lot, driving up rates in an effort to rein in inflation. But the decline during the past 15 years or so - and especially since the financial crisis -
goes way beyond a simple normalisation. Something unusual is happening.
That's worrying for macroeconomists, because it means
old theories may be wrong. It's also worrying for central bankers because it constrains their actions (nominal interest rates can't be pushed below zero) even as it increases the uncertainty under which they are forced to make their decisions.
So why are rates so bizarrely low? Interest rates are set in markets, where borrowers meet lenders (broadly defined).
Any explanation for falling rates must involve an increased desire to lend, a decreased desire to borrow, or both. One common theory is that central banks are responsible. This makes sense to most people, since we all hear that the US Federal Reserve, or the Bank of Japan, has a policy of holding interest rates near zero. But
just because central banks are setting their rate targets at zero doesn't mean they have to work very hard to achieve that target.