The so-called efficiency market refers to the market situation in which the market price can fully and quickly reflect all relevant information.

It has three premises:

1。 There are a large number of investors, and investors all aim at maximizing profits.

2。 Any information related to futures investment enters the market randomly.

3。 Investors can react and adjust quickly to new information.

It was put forward by American financier Fama.

So for your question, its effectiveness lies in the consistency of price and information.