What Is Intraday Buying Power?

Intraday buying power is the maximum dollar value of securities a pattern day trader can day trade — up to 4x the maintenance margin excess in the account, under FINRA rules. It is recalculated each morning from the prior close, does not carry overnight, and using all of it magnifies every adverse move roughly fourfold.

The definition, in plain English

Intraday buying power — brokers also call it day-trading buying power (DTBP) — is the maximum market value of securities you can day trade (open and close in the same session) in a margin account that has been flagged as a pattern day trader. Under FINRA's day-trading margin rules, it is generally 4x your maintenance margin excess as of the close of the prior business day.

Maintenance margin excess is simply your account equity minus the maintenance margin required to hold your existing positions. More excess equity means more intraday buying power; positions you are already carrying eat into it.

The 4x formula, with real numbers

Example 1 — a flat account (hypothetical):

Account equity: $30,000, all cash in a margin account, no open positions
Maintenance requirement: $0
Maintenance excess: $30,000 − $0 = $30,000
Intraday buying power: 4 × $30,000 = $120,000
Overnight buying power: 2 × $30,000 = $60,000

Example 2 — the same rule with a position on the books (hypothetical). Say the account holds $20,000 of marginable stock plus $20,000 cash, with no margin loan. Equity is $40,000. At a 25% maintenance requirement, the stock requires 0.25 × $20,000 = $5,000. Maintenance excess is $40,000 − $5,000 = $35,000, so day-trading buying power is 4 × $35,000 = $140,000. Note that brokers can impose stricter house requirements, so your platform may show less than the regulatory maximum.

Intraday vs. overnight buying power

	Intraday (day-trading) BP	Overnight BP
Multiple	Up to 4x maintenance margin excess	Roughly 2x (Reg T 50% initial margin)
Applies to	Positions opened and closed the same session	Positions held past the close
Calculated	From the prior day's close	At the time of purchase
If exceeded	Day-trading margin call	Reg T (Fed) margin call

The gap matters: a position sized to fit your 4x intraday limit may be twice too large to hold overnight. Carrying it past the close can trigger a margin call even though the entry itself was allowed.

Why it resets every morning

Intraday buying power is computed once, from your maintenance excess at the prior day's close. That has two practical consequences. First, profits booked during today's session generally do not raise today's limit — they show up in tomorrow's calculation. Second, the number does not accumulate: unused intraday buying power today does not roll into tomorrow. Some brokers also update a real-time figure that can shrink during the day as losses reduce your equity, and their house version is often more conservative than the FINRA floor.

The danger of maxing it out

Using the full 4x means every percentage move in your positions hits your equity about four times as hard. Continuing the hypothetical above: with $30,000 equity deploying the full $120,000, a 2% adverse move costs 0.02 × $120,000 = $2,400 — an 8% hit to equity in one session. A 25% adverse move on that exposure would equal the entire $30,000 account. Leverage is symmetric on paper, but a string of leveraged losses shrinks the equity that all future position sizes are built on.

There is also a rules-based penalty. Exceeding your day-trading buying power triggers a day-trading margin call: while it is outstanding you are typically limited to 2x maintenance excess, and if it is not met within five business days the account can be restricted to trading on a cash-available basis for 90 days. Deposits made to meet the call generally must remain in the account for two business days.

Leverage does not create an edge — it scales whatever results you already have, in both directions. Public statistics consistently show most retail day traders lose money; see the sourced numbers at day trading success rate statistics. All figures on this page are hypothetical illustrations, not projections.

Cash accounts vs. margin accounts

The 4x figure only exists in margin accounts. A cash account works differently:

No leverage: you can buy only what settled cash covers — buying power is your settled balance, not a multiple of it.
PDT-exempt: the pattern-day-trader rule (4+ day trades in 5 business days, $25,000 minimum equity) applies to margin accounts; cash accounts are exempt.
Settlement-bound: under T+1, proceeds from a sale settle the next business day. Spending unsettled funds and selling before settlement risks good-faith violations, which can lead to restrictions.

In short: margin accounts trade a bigger intraday limit for the PDT rules and leverage risk; cash accounts trade slower capital recycling for exemption from both.

Sizing a day trade to your risk instead of your maximum buying power is the core discipline — our free position size and risk/reward calculators at /tools/ do the arithmetic, and how to manage trading risk covers the framework. ClaudeQuantAlgo publishes a timestamped, loss-inclusive record — including a hypothetical 161-trade backtest that lost money (46.6% simulated win rate, 0.82 profit factor) — at /record/. Education and research only, not financial advice.

Common questions

What is intraday buying power?

Intraday buying power (day-trading buying power) is the maximum market value of securities a pattern day trader can day trade in a margin account — generally 4x the account's maintenance margin excess as of the prior day's close, under FINRA rules. It applies only to positions closed the same session; overnight holds fall back to roughly 2x under Reg T.

Why is intraday buying power 4x instead of 2x?

FINRA's day-trading margin rules allow pattern day traders 4x maintenance margin excess for same-day positions because the exposure is not carried overnight. Positions held past the close are subject to Regulation T's 50% initial margin, which works out to roughly 2x. Brokers can set stricter house limits than either figure.

Does intraday buying power reset every day?

Yes. It is recalculated each morning from your maintenance margin excess at the prior day's close. Gains booked during today's session generally do not raise today's limit, and unused buying power does not carry forward. Many brokers also display a real-time number that can shrink intraday as losses reduce equity.

Do cash accounts have intraday buying power?

Not in the 4x sense — that multiple only exists in margin accounts. A cash account can buy only what settled cash covers. Cash accounts are exempt from the pattern-day-trader rule, but under T+1 settlement, sale proceeds are not settled until the next business day, and trading with unsettled funds risks good-faith violations.

See the process with your own eyes. The desk posts trigger-based cards to a public, timestamped record — losses included — and published the backtest where its own raw scanner loses. The scoreboard is free to watch. Join the floor →

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Last updated 2026-07-15 · ClaudeQuantAlgo Research Desk · research and education only.

Disclosures. ClaudeQuantAlgo is a research and education community. Nothing on this page constitutes financial, investment, legal, or tax advice, or a recommendation to buy or sell any security or derivative. No profit promises are made, ever — trading stocks, options, and forex involves substantial risk of loss; options positions can lose 100% of their value. The public scoreboard reflects a model ("paper") desk — no real money. Past performance — real, paper, or simulated — never guarantees future results. Hypothetical and simulated results have inherent limitations and no representation is made that any account will or is likely to achieve similar profits or losses. ClaudeQuantAlgo is not a registered investment adviser or broker-dealer. You are solely responsible for your own trading decisions. Never risk money you cannot afford to lose.