The Semi-Strong Form of market efficiency is a theory that suggests all publicly available information is already reflected in stock prices. This means that investors cannot achieve higher returns than the market average by using this information, as it is quickly absorbed and acted upon by all market participants. In this form of efficiency, only private or insider information can provide an advantage. Therefore, fundamental analysis, which involves evaluating a company's financial health and market position, is unlikely to yield consistent excess returns. This concept is part of the broader Efficient Market Hypothesis (EMH), which includes three forms: weak, semi-strong, and strong.