You generally do not pay margin interest on day trades that open and close in the same session. Brokers calculate margin interest from the debit balance sitting in your account at the end of the trading day, so a position bought and sold before the close leaves a zero balance and produces a zero interest charge.1Fidelity. Margin Details The rule flips the moment you hold anything overnight.
Why Intraday Margin Is Free
Margin interest works as a daily snapshot, not a running meter. After the market closes, your broker looks at the borrowed balance in your account, and that figure is what gets charged. Buy $50,000 of stock on margin at 10:00 AM, sell it by 3:30 PM, and the borrowed funds are repaid before the daily ledger is finalized. There is no per-minute or per-hour borrowing fee.
That’s why day trading on margin can be significantly cheaper than swing or position trading on margin. You get the leverage during market hours without accumulating interest. The catch: it only works when you actually flatten every position before the close. One forgotten open trade converts a free intraday loan into a fee-bearing overnight obligation.
When You Do Start Paying
The moment a margin-funded position stays open past the close, your broker records a debit balance that rolls into the next business day. Interest accrues daily on that balance, including weekends and holidays, until you repay it by selling the securities or depositing cash. Most brokers use a 360-day year in the calculation. On a $10,000 margin balance at 8% annually, the daily charge works out to about $2.22 ($10,000 × 0.08 ÷ 360). Charges accumulate and are typically posted to your account statement monthly.2U.S. Securities and Exchange Commission. Investor Bulletin: Interested in Margin? Understand Interest
How the Rate Is Set
Brokers don’t charge a flat rate. They use a tiered schedule where larger debit balances get lower rates. In late 2025, one major broker’s schedule ran from 11.825% for balances under $25,000 down to 10.075% for balances between $250,000 and $500,000, with negotiable rates above that.3Charles Schwab. Schwab Margin Rates and Requirements These rates float with the broker call rate, which tracks Federal Reserve policy. When the Fed raises rates, your margin interest rises with them.
A $50,000 debit balance at 10% costs roughly $13.89 per day, or about $417 per month. That’s a drag your trades need to overcome before you see any real profit.
The $25,000 Pattern Day Trader Rule
Even with intraday interest at zero, active day traders run into a separate cost of doing business: the pattern day trader minimum. FINRA Rule 4210 defines a pattern day trader as anyone making four or more day trades within five business days, unless those day trades represent 6% or less of total trading activity in that same window.4FINRA. FINRA Rule 4210 – Margin Requirements Once flagged, your account must hold at least $25,000 in equity at all times, measured as cash plus the market value of eligible securities.
Drop below $25,000 and you get a margin call with five business days to deposit funds. Miss the deadline and your account gets restricted to cash-only transactions for 90 days or until you meet the requirement, whichever comes first. You can still trade during that freeze, but only with fully settled cash rather than margin buying power.
Intraday vs. Overnight Buying Power
Pattern day traders in good standing get more leverage during market hours than they do overnight. Federal Reserve Regulation T sets initial margin at 50% of a purchase, so $50,000 in equity normally supports $100,000 of stock overnight. For intraday positions, FINRA Rule 4210 grants pattern day traders buying power equal to four times their maintenance margin excess.4FINRA. FINRA Rule 4210 – Margin Requirements That same $50,000 account could support up to $200,000 in day trades, as long as every position is closed by the end of the session.
This ties leverage back to the interest question. The 4:1 intraday ratio is attractive precisely because it carries no interest cost when you close before the bell. Hold that same $200,000 position overnight and you’d need $100,000 in equity to meet the 50% Regulation T requirement, with interest accruing on the $100,000 borrowed portion immediately.
Fees That Apply Even When Interest Is Zero
Zero margin interest doesn’t mean zero cost. Every sell order carries mandatory regulatory fees.
SEC Section 31 Fee
The SEC charges a fee on sales of exchange-listed securities. As of April 4, 2026, the rate is $20.60 per $1,000,000 in sale proceeds.5U.S. Securities and Exchange Commission. Section 31 Transaction Fee Rate Advisory for Fiscal Year 2026 On a $10,000 sell order, that’s about two cents. The rate is adjusted periodically based on federal budget requirements.
FINRA Trading Activity Fee
FINRA assesses a separate fee on every sale of a covered equity security. The current rate is $0.000195 per share, capped at $9.79 per trade.6FINRA. Fee Adjustment Schedule For a 1,000-share sell order, the TAF comes to about 20 cents. The cap helps traders moving large blocks, but for small-lot scalpers making hundreds of trades, the per-share cost is what matters.
Both fees apply only to the sell side and are deducted automatically from your proceeds. They’re volume-based, not time-based, so holding for three seconds costs the same as holding for three hours.
Short Sale Borrow Fees
Short sellers face an additional variable cost. When you short a stock that’s hard to borrow because of limited supply or high demand, the daily borrow fee can dwarf any profit from the trade. These fees fluctuate with lending market conditions and are charged daily for as long as the short position stays open. Unlike margin interest on long positions, borrow fees can apply even to intraday shorts at some brokers, so checking the borrow rate before entering a short day trade is worth the extra few seconds.
Tax Treatment of Margin Interest You Do Pay
Margin interest paid on overnight positions is deductible as investment interest expense, but capped at your net investment income for the year.7Office of the Law Revision Counsel. 26 U.S. Code 163 – Interest Net investment income includes interest, ordinary dividends, and short-term capital gains, minus any investment expenses other than interest. Anything above that cap carries forward to the next tax year.
Qualified dividends and long-term capital gains are normally excluded from the calculation because they receive preferential rates. You can elect to include them, which raises your deduction cap but strips those gains of their favorable rate and taxes them as ordinary income. The IRS wants the calculation reported on Form 4952 unless your investment income from interest and ordinary dividends already exceeds your margin interest expense and you have no carryforward from prior years.8Internal Revenue Service. Publication 550 (2025), Investment Income and Expenses
For pure day traders who rarely hold overnight, margin interest is often negligible on the return. Traders who occasionally swing on margin should track these costs carefully. Every dollar of margin interest you fail to deduct is money left on the table.