The "Weak Form" is a concept in finance that suggests that current stock prices reflect all past trading information. This means that historical prices and trading volumes are already incorporated into the stock's current value, making it difficult to predict future price movements based solely on this data. In the context of the Efficient Market Hypothesis, the Weak Form asserts that technical analysis, which relies on historical price patterns, is ineffective for achieving consistent investment returns. Investors who believe in this form argue that any potential gains from analyzing past prices are quickly absorbed by the market.