Two margin rulebooks are live at the same time. FINRA Regulatory Notice 26-10 made the new intraday margin standard effective on 4 June 2026, and firms that need longer can phase it in until 20 October 2027, so the framework your account sits under today is your broker's choice rather than a date on a calendar. The difference is worth $25,000: the old rules impose a minimum equity requirement of $25,000 on a customer designated a pattern day trader, and under the new ones there is no $25,000 minimum equity requirement for day trading and no pattern day trader designation based on counting trades.

What the old day-trading rules measure

The old framework counts. FINRA rules define a pattern day trader as any customer who executes four or more day trades within five business days, provided that the number of day trades represents more than six percent of the customer's total trades in the margin account for that same five-business-day period, and a day trade is the purchase and sale, or sale and purchase, of the same security on the same day in a margin account.

Designation triggers two figures. The $25,000 minimum equity has to be in the account before any day trading and maintained at all times, and cannot be met by cross-guaranteeing separate accounts; day-trading buying power runs to four times maintenance margin excess as of the close of business of the previous day for equity securities. Exceed that cap and the firm issues a day-trading margin call. The customer has five business days to meet it, buying power is cut to two times maintenance margin excess in the meantime, and an unmet call restricts the account to trading on a cash available basis for 90 days or until the call is met.

What the new intraday standard measures instead

The new framework measures exposure at the moment it exists. FINRA Rule 4210 now defines an intraday margin level, or IML: the amount of cash the customer could withdraw while still having the maintenance margin required, or the additional cash the customer would need to deposit to reach it. An intraday margin deficit is the largest negative IML following an IML-reducing transaction during the trading day, and an IML-reducing transaction is any transaction that reduces the amount the customer could withdraw while still meeting the maintenance margin requirement, such as a short sale or a purchase other than to cover a short.

The deficit then has its own clock. A member must require an intraday margin deficit to be satisfied as promptly as possible, and the deficit remains outstanding until satisfied or until immediately after the close of business on the 15th business day after it arose. Make a practice of missing the fifth-business-day deadline and the firm must prevent the customer from creating or increasing a short position or debit balance for 90 calendar days; a single deficit under 5 percent of equity or $1,000, or one arising from extraordinary circumstances, does not count toward that practice. The amendments do not change the regular maintenance margin requirements as they exist today, and they preserve the $5 million threshold under the portfolio margin provisions.

Example: $30,000 of equity under each framework

An example, and a mechanism rather than a strategy. An account holds $30,000 of equity and no positions at the previous close, so its maintenance margin excess is $30,000.

Under the old framework that account clears the $25,000 minimum, and four times maintenance margin excess puts day-trading buying power at 4 times $30,000, or $120,000.

Under the new one neither number is tested. What is tested is the IML after each IML-reducing transaction. Buy $120,000 of stock intraday and the 25 percent maintenance requirement under Rule 4210(c)(1) is 0.25 times $120,000, or $30,000, exactly the equity, so the IML is $0 and no deficit arises. Buy $160,000 instead and the requirement is 0.25 times $160,000, or $40,000, against $30,000 of equity: an intraday margin deficit of $10,000. That $10,000 has to be satisfied as promptly as possible; only a repeated practice of missing the fifth-business-day deadline, not this single deficit alone, triggers the 90-calendar-day restriction on new short positions and debit balances.

Same account, same trade, two different constraints.

Four questions for the firm, and the date to ask again

The rulebook does not answer which framework applies to you; the firm does. FINRA's own guidance is to contact your firm to be sure you understand how the changes affect your account.

  1. Is this account on the day-trading margin rules or the intraday margin standard today, and on what date does it move?
  2. If it is still on the old rules, what is the house minimum equity, given that $25,000 is a floor a firm can raise?
  3. If it is on the new standard, how is the intraday margin deficit calculated and displayed during the session?
  4. What house maintenance percentage sits above the 25 percent in Rule 4210(c)(1)?

Ask again before 20 October 2027, because that is the last date on which an answer can still be "the old rules". The rest of the account's mechanics, from how a margin call ends to what the funding split does to gains and losses, does not change with the transition; only the day-trading layer does, and leverage arithmetic still runs underneath it.

Source references

Primary sources used for this guide. Follow the links for the original scope, definitions and conditions.