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Everyone knows a shiny new bridge when they see one. Quantitative easing, on the other hand, has been a mystery to all but hardened anoraks until zero interest rates started to loom late last year. Policymakers worldwide now pin their hopes on quantitative easing’s ability to complement traditional fiscal stimuli as a means of boosting demand.
Even if they feel boosting money supply worth a try, few have a genuine conviction that it will work. There are three big problems with central banks buying unsterilised financial assets. The first is signalling. The normal process of tinkering with interest rates is based on eons of data on the effect on growth and inflation. That in turn provides a framework round which future rate moves can be forecast. Quantitative easing, however, is messy. That calls for clear targets. But based on what? Targeting particular measures of money supply, bank lending (as Japan did) or long-dated gilt yields is tricky.
Even with targets, the second problem is working out exactly how much quantitative easing is enough. Very simply, whether raising the money in circulation boosts incomes depends also on what economists call the “velocity” of money. If those selling assets to the central bank simply put their spoils on deposit, for example, the potential boost from the increase in money will be tempered. Knowing the velocity of money therefore is crucial. Yet this number is hard to pin down.
The final headache lies in selecting which assets to buy. As the Bank of England showed last week, most central banks go for government bonds. But these tend to be owned by financial institutions, not the ailing companies and households that need the money most. Besides, government bonds are already super liquid. It would be preferable for central banks to swap cash for harder-to-shift assets such as commercial paper. Another plus would be that purchases of such assets would remove their liquidity discount, giving the likes of the Bank at least a fighting chance of recovering their money when things finally recover enough to sell again.
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