Day traders generally use leverage such as margin loans; in the United States, Regulation T permits an initial maximum leverage of 2:1, but many brokers will permit 4:1 intraday leverage as long as the leverage is reduced to 2:1 or less by the end of the trading day. In the United States, based on rules by the Financial Industry Regulatory Authority, people who make more than 3 day trades per 5-trading day period are termed pattern day traders and are required to maintain $25,000 in equity in their accounts. However, a day trader with the legal minimum of $25,000 in their account can buy $100,000 (4x leverage) worth of stock during the day, as long as half of those positions are exited before the market close. Because of the high risk of margin use, and of other day trading practices, a day trader will often have to exit a losing position very quickly, in order to prevent a greater, unacceptable loss, or even a disastrous loss, much larger than their original investment, or even larger than their account value. Since margin interest is typically only charged on overnight balances, the trader may pay no interest fees for the margin loan, though still running the risk of margin calls. Margin interest rates are usually based on the broker's call rate.