The study looked at how insider trading laws affect the stock market. After a court ruling made it harder to prosecute insider trading, there was more suspicious trading in the affected area. This led to less overall trading in those stocks, making it harder for regular investors to buy and sell. The prices of these stocks were also more affected by trades, meaning that insider trading can hurt everyone in the market. The results show that insider trading laws are important for keeping the market fair, and when these laws are weakened, insider trading can harm investors.