• (Speculation of) quantitative easing has an upward effect on commodity prices. As Western countries and Japan have to import a lot of commodities, that inhibits growth.
• Quantitative easing forces investors to step into ever-riskier investments. That could cause an enormous blow in a subsequent recession.
• Should QE achieve to (temporarily) lift economic growth through higher credit extension, inflation (expectations) will rise immediately as the enormous amount of money created flows into the real economy. Investors in bonds will anticipate this, and will begin selling bonds – they lose more value the higher inflation expectations – so there is a high risks that interest rates rise even more than inflation. The result is that it becomes increasingly expensive for the both the government and the private sector to (re)finance debts, and risks of bankruptcy loom.
• If the central bank does try to avert higher inflation and interest rates when the economy starts growing again, it has to drain the money it has pumped into the banks before. The more money was printed, the more money has to be withdrawn. To the extent that high money creation has boosted asset prices, the opposite occurs if liquidity is withdrawn from the system. The more money has been printed, the more downward pressure there will be on asset prices if the central bank reverses this process.
• Japanis still struggling with the additional problem of the financial markets easily interpreting quantitative easing as monetarily financing budget deficits. As soon as that happens, interest rates will rise and the Japanese government will be bankrupt.