The Different Types of Efficiency Weak Form Security prices reflect all information found in past prices and volume. ■ Semi-Strong Form Security prices reflect all p publicly available information. Strong Form Security prices reflect all information-public and private. 99 The Different Types of Efficiency The Different Types of Efficiency ƒ Weak Form – Security prices reflect all information found in past prices and volume. ƒ Semi-Strong Form – Security prices reflect all publicly available information. ƒ Strong Form – Security prices reflect all information—public and private