S. Cecchetti und K. Schoenholtz befassen sich mit dieser Frage in einem aktuellen Blog-Beitrag. Sie diskutieren außerdem, wie groß der Rückgang der Bilanzsumme der Fed letztendlich wohl sein wird und ob die Reduzierung ein Problem für die Geldpolitik darstellen könnte.
Hier erstmal die Entwicklung der Zentralbankbilanzsummen der entwickelten Volkswirtschaften:
"In financial systems where banks dominate, central bank balance sheets will be larger. Where reserve requirements are high, central banks need bigger balance sheets to satisfy commercial bank reserve needs. Where payments technology relies heavily on currency (rather than electronic transfers), the public holds more cash and commercial banks also seek larger reserve buffers to meet payments obligations. Policymakers focused on exchange rate stability typically need big foreign currency reserves. Finally, central banks that are not politically independent may hold a large volume of assets in their role as the government’s bank, allowing them to target favored assets. In contrast, independent central banks tend to hold small portfolios of relatively short-term government securities. Such “asset neutrality” establishes a bulwark against influence over the central bank by the fiscal authority.These five factors go a long way toward explaining why emerging market central bank balance sheets tend to be larger than those in advanced economies."
Die Autoren schlussfolgern am Ende des Beitrags:
"So how much is the Fed’s balance sheet eventually likely to shrink? Plenty. There seems little desire to replace its $1.7 trillion of mortgage-backed securities as they mature. The remaining assets would be sufficient to support more than $1 trillion of bank reserves. But monetary policy can be implemented efficiently with few (or even no) reserves. Our view is that the most likely result is a long-run Fed portfolio at most half its current size, even if policymakers decide they wish to provide significant high-quality liquid assets, and substantially less if they do not.It will take many years to get to this lower long-run level of assets, but making that transition ought not be a problem for setting monetary policy. With the ability to pay interest on reserves, combined with other new instruments like reverse repo, the Fed should be able to adjust its policy interest rate regardless of the size of its balance sheet."