Notice of RetractionThe information reaction changes and efficiency improvements of Chinese stock market

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

The presenting author of this paper has the option to appeal this decision by contacting TPII@ieee.org.

The purpose of this paper is to investigate whether the stock market efficiency improved in the past twenty years based on the information reaction changes. We found Chinese stock market has an obvious different characteristic of news reaction with developed market after market condition dividend. Market reacts to good news more and leverages only to be significant in downward periods. But the asymmetry extent changed to be lower and the react timeliness changed to be higher which means the market efficiency is in a increasing process. Our test results brought more indicators to investors, supervisors and regulation constitutors for further development of our stock market.