Answer: unexpected information only.

## Explanation In an efficient market, asset prices should already reflect all available information, including expected information. Therefore: 1. **Expected information** is already incorporated into prices before it's officially released. Market participants anticipate this information based on forecasts, consensus estimates, and other available data. 2. **Unexpected information** (also called "surprises" or "shocks") is new information that was not anticipated by the market. This is what causes prices to adjust. 3. The **efficient market hypothesis** states that prices fully reflect all available information. If information is expected, rational investors would have already acted on their expectations, so the actual release shouldn't cause price changes. 4. Only **unexpected information** contains new information that wasn't already priced in, causing asset prices to react. **Example**: If a company is expected to report earnings of $1.00 per share and actually reports $1.00, the price likely won't change much. But if they unexpectedly report $1.20 or $0.80, the price will react to this surprise. Therefore, in an efficient market, asset prices react primarily to unexpected information.

Author: LeetQuiz .