Answer: Based on the information collected in asset prices, three types of efficiency stand out:
Weak efficiency: Asset prices reflect all historical information. Therefore, historical prices and their volume have no predictive capacity for their future evolution.
Semi-strong efficiency: In this case the prices reflect both the historical and public information available on the assets. An investor could only obtain returns higher than those of the market through the use of private or privileged information.
Strong efficiency: Asset prices reflect all existing information (historical, public and private). If an investor had access to privileged information, the price would adjust quickly, and would not allow to benefit from that information.
