Define information asymmetry in the context of Efficient Markets.

The Australian share market is a public one where all buyers and sellers gather in one central digital place, to trade shares. Market Information about all trade is available near-instantaneously as it happens and is easily available to the market. The Australian property market operates privately, where transactions are dispersed across the country and where market transactions need not be disclosed to the public. Describe the difference in efficiency, information asymmetry and reaction of prices to information between the share market and property market.

What are the implications of this difference of information asymmetry between these two markets, for the opportunities to earn above-market returns in each?