Summary of the Day-Trading Margin Requirements
The rules adopt the term "pattern day trader," (PDT) which includes any margin customer that day trades (buys then sells or sells short then buys the same security on the same day) four or more times in five business days, provided the number of day trades are more than six percent of the customer's total trading activity for that same five-day period. Under the rules, a pattern day trader must maintain minimum equity of $25,000 on any day that the customer day trades. The required minimum equity must be in the account prior to any day-trading activities. If the account falls below the $25,000 requirement, the pattern day trader will not be permitted to day trade until the account is restored to the $25,000 minimum equity level.
The rules permit a pattern day trader to trade up to four times the maintenance margin excess in the account as of the close of business of the previous day. If a pattern day trader exceeds the day-trading buying power limitation, the firm will issue a day-trading margin call to the pattern day trader. The pattern day trader will then have, at most, five business days to deposit funds to meet this day-trading margin call. Until the margin call is met, the day-trading account will be restricted to day-trading buying power of only two times maintenance margin excess based on the customer's daily total trading commitment. If the day-trading margin call is not met by the fifth business day, the account will be further restricted to trading only on a cash available basis for 90 days or until the call is met.
In addition, the rules require that any funds used to meet the day-trading minimum equity requirement or to meet any day-trading margin calls remain in the pattern day trader's account for two business days following the close of business on any day when the deposit is required. The rules also prohibit the use of cross-guarantees to meet any of the day-trading margin requirements.
this however, does not apply to retail traders who are customers of market makers (OTC TRADES, bucket brokers). so does not apply to 99.9% of "day traders" who trade forex with any broker who accepts retail clients.