The efficient markets hypothesis implies that:

stock prices are never too high or too low; they always accurately reflect the underlying value of the company.

investors don't make mistakes when determining when to buy and sell stocks.

it is very difficult to systematically pick stocks that beat the market in the long$-$run without "inside information"

the market is always right, so there is no need to invest your money

it is easy to earn above market rates of return using the appropriate investment strategies at the right time.