Margin trading refers to the practice of borrowing funds from a broker or an exchange in order to trade financial assets such as stocks, bonds, currencies, or cryptocurrencies. Margin trading allows investors to leverage their capital and increase the potential profit on their trades, but it also increases the risk of losses.

When an investor engages in margin trading, they put up a certain amount of their own funds as collateral, known as the initial margin. The broker or exchange then provides additional funds, known as the margin loan, to increase the investor's buying power. The ratio of the margin loan to the investor's own funds is known as the leverage ratio.

Margin trading can be risky because losses can exceed the initial investment. If the value of the assets being traded falls below a certain level, known as the maintenance margin, the investor may receive a margin call, requiring them to deposit additional funds to maintain the required margin level. If the investor is unable to meet the margin call, the broker or exchange may sell the assets to recover the loaned funds, which can result in significant losses for the investor. Therefore, margin trading should be approached with caution and only undertaken by experienced investors who fully understand the risks involved.