> Where do you get the idea that the EMH assumes perfect information?
The grounding of the EMH is a consequence of rational actor theory which assumes perfect information.
It could be true without the rational actor theory more generally or perfect information in particular being true, but there is no reason to expect it to be true except the assumption of those theoretical foundations in which it is grounded.
Its difficult to falsify the EMH, since it doesn't actually rule out any outcomes, it just asserts that if market-beating outcomes occur, they are because of luck rather than strategy. As such, there is no result that is strictly inconsistent with the EMH. (Further difficulties arise since, if one rejects the EMH, but still assumes that market participants do efficiently apply the information that is available to them, any market-beating strategy would need to be kept secret to avoid being adopted generally in the market, and thus no longer be market-beating, so any test of EMH has to be able to distinguish between result of luck and results of covert strategy.)
The grounding of the EMH is a consequence of rational actor theory which assumes perfect information.
It could be true without the rational actor theory more generally or perfect information in particular being true, but there is no reason to expect it to be true except the assumption of those theoretical foundations in which it is grounded.
Its difficult to falsify the EMH, since it doesn't actually rule out any outcomes, it just asserts that if market-beating outcomes occur, they are because of luck rather than strategy. As such, there is no result that is strictly inconsistent with the EMH. (Further difficulties arise since, if one rejects the EMH, but still assumes that market participants do efficiently apply the information that is available to them, any market-beating strategy would need to be kept secret to avoid being adopted generally in the market, and thus no longer be market-beating, so any test of EMH has to be able to distinguish between result of luck and results of covert strategy.)