Stimulus and easy monetary policy has led to stock market exuberance in a number of developed economies.
Concluding whether an index is fairly valued or overvalued simply by looking at its quoted numerical value is not a valid exercise, since the index is capitalization adjusted and float adjusted.
Westpac (WBC), Commonwealth Bank (CBA), and ANZ Banking Group (ANZ) are all trading at PE ratios of above 15.
This is one of the ways in which low interest rates can create a "wealth effect" and stimulate investor and consumer confidence.
Whether or not the market is in a "bubble", however, is a different question.