Random walk theory is a theory that suggests that stock market prices and other financial asset prices move randomly and are not predictable. It is based on the idea that changes in asset prices occur randomly, and that past prices and market trends are not reliable indicators of future prices. The theory assumes that at any given moment, stock prices reflect all available information, including past prices, financial reports, and news. Therefore, it is impossible to predict future prices based on past prices or other indicators. The only way to predict future prices is to know all the information that will be available in the future.

According to the theory, changes in asset prices occur randomly, and there is no way to predict future prices based on past prices or other indicators. This means that stock prices and other financial asset prices are unpredictable in the short term and that any attempt to time the market or predict future prices is essentially a game of chance. One important implication of the random walk theory is that it is difficult to consistently outperform the market by picking individual stocks or timing the market. The theory suggests that the most rational strategy for investors is to hold a diversified portfolio of assets, which reflects the overall performance of the market.

Advantages of Random Walk Theory:

• Simplicity: Random walk theory provides a simple explanation of stock market movements, suggesting that changes in stock prices are largely unpredictable and independent of past prices or market trends.

• Efficient Market Hypothesis: Random walk theory is closely linked to the efficient market hypothesis, which suggests that stock prices reflect all available information, making it difficult for investors to consistently beat the market by picking individual stocks or timing the market.

• Diversification: The theory implies that diversification is an important strategy for investors, as holding a diversified portfolio of assets can capture the overall performance of the market.

Disadvantages of Random Walk Theory:

• Limited applicability: The theory assumes that market movements are completely random, which may not always be the case. Some financial experts argue that there are predictable patterns in financial markets that can be exploited by skilled investors.

• Short-term unpredictability: While the theory suggests that stock prices are unpredictable in the short term, this does not necessarily mean that they are completely random or unpredictable in the long term. It is possible for trends and patterns to emerge over longer time frames.

• Ignores fundamental analysis: Random walk theory does not take into account fundamental analysis, which involves analyzing a company's financial statements and other non-market factors that may influence its stock price. This may limit its usefulness for investors who rely on fundamental analysis to make investment decisions. 

It is important to note that the random walk theory has been subject to criticism and debate among economists and financial experts, who argue that there are some predictable patterns in financial markets that can be exploited by skilled investors. Moreover, the assumption of randomness has been questioned, with some suggesting that market movements may be influenced by factors such as investor behavior and sentiment, which may not be entirely random.