As one effect of a decline in longer-term interest rates due to government bond purchases, it is expected that confidence will improve among investors, firms, and households, thereby encouraging a shift of investment from government bonds and other safe assets to a wider range of risk assets, such as corporate bonds, equities, and overseas assets, and this in turn will lower risk premiums of these assets and increase asset prices.
This can be considered a portfolio balance effect in a broad sense and means an improvement in wide-ranging financial conditions. In such a situation, demand for government bonds will decline and there will be a certain amount of upward pressure on term premiums of government bonds (that is, a rise in the extra interest rate required for risk associated with long-term bond investment).