Day trading buying power is the maximum dollar amount of stock you can buy and sell within the same trading session using your own equity plus money borrowed from your broker. Under the pattern day trader rules still in effect at most brokerages, it equals four times your maintenance margin excess from the prior day’s close. That framework is being replaced: FINRA’s new intraday margin standards, approved by the SEC on April 14, 2026, drop the pattern day trader designation and the $25,000 minimum in favor of a real-time 25% maintenance requirement, with an effective date of June 4, 2026 and a phase-in deadline of October 20, 2027.1FINRA. Regulatory Notice 26-10 Which set of numbers governs your account right now depends on your broker.
How Buying Power Is Calculated Under the Current Rules
If you’re classified as a pattern day trader, your day trading buying power equals four times your maintenance margin excess as of the prior day’s close.2FINRA. FINRA Rule 4210 – Margin Requirements Maintenance margin excess is the equity in your account minus the maintenance margin your open positions already require.3FINRA. Day Trading
A worked example. Your account holds $40,000 in equity. Your existing positions carry a $10,000 maintenance requirement. Excess is $30,000. Multiply by four and you have $120,000 in day trading buying power for the next session. That figure is fixed for the whole day based on the previous night’s closing values. Profits you book intraday do not increase it until after the close.
To stay classified as a pattern day trader in the first place, you need at least $25,000 in equity in the margin account at all times, held as any mix of cash and eligible securities.2FINRA. FINRA Rule 4210 – Margin Requirements Drop to $24,800 on a bad day and your broker cuts off day trading privileges until you top the account back up. There’s no grace period.
House Requirements Can Shrink the Number on Paper
FINRA’s 25% maintenance margin on long equity positions is the regulatory floor.2FINRA. FINRA Rule 4210 – Margin Requirements Your broker almost certainly requires more. Many firms set a house baseline at 30% and raise it further for individual stocks based on volatility, liquidity, and concentration. They can raise these house requirements at any time without advance written notice.4FINRA. Margin Calls
Some brokers run dynamic models that estimate how far a stock could move in a day and set the maintenance requirement to match. A volatile small-cap might carry a 75% or even 100% requirement, meaning you get no leverage on it at all. Before sizing a trade, check the specific requirement for that security on your broker’s platform. An account that looks like $120,000 in buying power on paper can carry substantially less once the actual maintenance requirements are applied.
Intraday vs. Overnight
The 4:1 leverage only applies to positions opened and closed in the same session. The moment you decide to hold something past the close, Regulation T’s initial margin requirement takes over: you need equity worth at least 50% of the position’s market value.5eCFR. 12 CFR Part 220 – Credit by Brokers and Dealers (Regulation T) That drops your effective leverage from 4:1 to 2:1.
This gap catches traders often. Use most of your intraday capacity, fail to close before the bell, and your account may not have enough equity to support the overnight requirement. You get an immediate margin call, or the broker liquidates part of the position for you. Many active traders leave a buffer, staying below their full 4:1 capacity in case a trade runs into the close.
Day Trading Margin Calls
Exceed your 4:1 buying power and you get a day trading margin call. You have five business days from the trade date to deposit enough cash or securities to cover the deficiency.2FINRA. FINRA Rule 4210 – Margin Requirements Miss it and your account gets restricted to cash-only trading for 90 days.6FINRA. FINRA Rule 4210 – Margin Requirements
Selling existing positions to cover the call is a common mistake. FINRA discourages it. Liquidating securities does release some maintenance margin, but the deficiency generally has to be met with new funds brought in from outside the account.6FINRA. FINRA Rule 4210 – Margin Requirements Repeated violations can lead to permanent removal of margin privileges or account closure.
Your Broker Doesn’t Have to Call First
A firm is not required to notify you before your equity drops below its minimum, and it doesn’t have to issue a margin call before selling securities in your account. Your broker can sell enough to pay off the entire margin loan, not just the deficiency, and you don’t get to pick which positions go.4FINRA. Margin Calls Fast markets can burn through maintenance margin in minutes. Counting on a courtesy call is one of the more expensive habits in day trading.
What Changes Under the 2026 Intraday Margin Rules
The new standards drop three things at once: the pattern day trader designation, the day-trade counting methodology, and the $25,000 minimum equity requirement. Brokerages that need more time can phase in the changes over 18 months from the June 4, 2026 effective date, with a final deadline of October 20, 2027.1FINRA. Regulatory Notice 26-10 Ask your broker which framework applies to your account.
Instead of counting day trades and applying a $25,000 floor, the new approach requires your brokerage to monitor the intraday margin deficit in your account. That deficit is the gap between the maintenance margin your positions require and the equity actually in your account at the point of highest exposure during the day.1FINRA. Regulatory Notice 26-10 You have to hold at least 25% of the market value of your long equity positions in equity throughout the whole trading day, not just at the close.7FINRA. Understanding the New Intraday Margin Requirements
The effect on buying power: it becomes tied to your actual positions and equity in real time rather than a static calculation from the prior day’s close. Start the day with $10,000 in equity and no positions, and you could in theory buy up to $40,000 in stock, because 25% of $40,000 is $10,000. The moment those positions move against you and equity drops, your capacity shrinks with it.
Consequences for an Intraday Deficit
If your account develops an intraday margin deficit, you’re expected to cover it as promptly as possible with cash or securities. Small deficits get some leeway: a shortfall equal to the lesser of 5% of account equity or $1,000 doesn’t count against you as a pattern of failure.1FINRA. Regulatory Notice 26-10 An unsatisfied deficit expires after 15 business days.
Repeated failures bite. If you develop a habit of not covering deficits promptly and still haven’t resolved one by the fifth business day, your broker must restrict the account for 90 calendar days. During that freeze you cannot open new positions or increase any debit balance.1FINRA. Regulatory Notice 26-10
Options and Cash Accounts Don’t Get the Multiplier
The 4:1 day trading multiplier applies to equity securities. Long options do not get margin leverage. FINRA Rule 4210 requires long calls and puts to be paid for in full: 100% of the premium, no borrowing.2FINRA. FINRA Rule 4210 – Margin Requirements Your buying power for buying options equals your available cash and any proceeds from settled trades, not the leveraged figure your platform shows for stocks. Short options and spread strategies have their own margin math that varies by strategy. If you trade both stocks and options intraday, track the two pools separately.
Cash accounts don’t have day trading buying power in the leveraged sense at all. Your capacity equals your settled cash balance, and under T+1 settlement money from a sale today isn’t available to fund a new purchase until tomorrow.8U.S. Securities and Exchange Commission. SEC Chair Gensler Statement on Upcoming Implementation of T+1 You avoid the pattern day trader threshold and margin risk, but rapid-fire round trips aren’t possible. Most active day traders accept margin exposure precisely because waiting for settlement is the alternative.