Three forms of market efficiency (stock markets)
There are three levels of market efficiency:
Weak form efficiency – the current pricing reflects the historical sequence of prices. In other words, knowledge of the past pricing patterns will not help in forecasting the future price trends.
Semi-strong from efficiency – current pricing fully reflects all information held in the public domain like the annual reports, revenue guidelines, any news etc.
Strong form efficiency – current pricing fully reflects all information held in the public and the private domain (information available only to the insiders of the company like the management, consultants and other critical and leadership positions).
