Cases involving company insiders manipulating stock prices are not uncommon in financial markets. This behavior is often considered illegal because it may violate securities laws, especially those related to insider trading and market manipulation. Here are some common manipulation techniques and some well-known cases: ### Manipulation techniques 1. **Insider trading**: Insiders use non-public material information (such as upcoming financial reports or major cooperation news) to buy and sell in order to gain benefits. 2. **False information release**: Spreading false or misleading information to influence stock prices, including publishing announcements or rumors through media, social networks, etc. 3. **Manipulation of market liquidity**: Artificially affecting supply and demand through large purchases or sales of stocks, thereby pushing up or down stock prices. 4. **Buybacks or special trading activities**: Companies influence their stock prices to rise through stock buyback programs or other unusual trading activities. 5. **Wash trading**: Insiders artificially create trading volume and support stock prices through frequent transactions between related accounts. ### Well-known cases 1. **Elon Musk and Tesla**: Although the specific details vary, Elon Musk has received attention for posting significant information about Tesla on Twitter. He claimed in 2018 that he was ready to take Tesla private and that "funding was secured", which caused the stock price to fluctuate wildly and subsequently triggered an investigation and legal action by the US Securities and Exchange Commission (SEC). 2. **Enron**: Although primarily a case of financial fraud, it also involved the release of false information to maintain stock prices. Enron's executives concealed the company's actual financial situation by fabricating financial data to keep the stock price high, which ultimately led to the company's collapse. 3. **Martha Stewart and ImClone**: Although it involved insider trading rather than direct manipulation of stock prices, Martha Stewart received attention for selling her shares after learning that ImClone executives were selling shares, thus avoiding losses. In these cases, insiders or related parties used improper means to influence stock prices, and most of them eventually led to legal investigations or even criminal charges. Regulatory agencies, such as the U.S. Securities and Exchange Commission (SEC) or the China Securities Regulatory Commission (CSRC), have strict regulations on these activities to protect the fairness and transparency of the market.