The study found that an increase in quantity associated with increased purchases of JGBs that was implemented at the outset of the introduction of quantitative easing policy worked on stock prices and foreign exchange rate in a significant manner. The effect of an increase in quantity without increases in JGB purchases was not significant.
As a study on the ultimate impact on economic activity and prices, time-series analysis by Honda, Kuroki and Tachibana (2007) is well known. There is also a recent study by Kimura and Nakajima (2013) and Shibamoto and Tachibana (2013).