However, in an extreme situation or high frequency band, mark-to-market mechanism can not catch the changing phase. When phase lag is larger than 90º, a negative feedback loop can become a positive feedback loop in characteristics. In this situation, what we need to do is to cut off this loop, thus we need a circuit breaker.
For example, US Federal Reserve Chairman Ben Bernanke wrote that changes in asset prices should affect monetary policy only to the extent that they affect the central bank’s forecast of inflation.