What does the Efficient-market hypothesis say about the securities prices?

The Efficient Market Hypothesis (EMH) asserts that securities prices fully reflect all available information at any given time. As a result, it suggests that it's impossible to consistently achieve higher returns than the overall market through stock selection or market timing, since any new information is quickly incorporated into prices. EMH is categorized into three forms: weak, semi-strong, and strong, each varying in the types of information considered. Ultimately, EMH implies that markets are efficient and that investors cannot easily outperform the market through analysis or trading strategies.