Margin trading is a mainstream leveraged investment mechanism widely used in US stock, European stock, and global foreign exchange trading markets, provided by formal licensed overseas brokerage institutions for qualified individual and institutional investors. Different from cash trading that relies entirely on investors’ own capital, margin trading requires users to deposit a certain percentage of self-owned funds as collateral (initial margin), and the brokerage provides matching leverage funds to expand the investor’s market trading scale. Overseas mainstream brokerage firms usually provide 2:1 to 5:1 leverage ratios for stock trading, and higher leverage ratios for foreign exchange and futures trading. This trading method amplifies investors’ profit space when the market trend is consistent with the investment judgment; however, it also significantly magnifies investment risks. When the asset price fluctuates adversely and the investor’s account equity falls below the maintenance margin standard set by the brokerage, the institution will issue a margin call, requiring the investor to supplement funds or liquidate positions forcibly. In the US financial market, margin trading is strictly regulated by the SEC (U.S. Securities and Exchange Commission), which clarifies initial margin ratios, maintenance margin standards, and forced liquidation rules to prevent systemic financial risks. For overseas financial practitioners and active retail investors, margin trading is an essential trading tool for flexible capital utilization, but it requires strict risk control awareness and market judgment ability, and is not suitable for novice investors with insufficient risk tolerance.