Cash and margin accounts: follow the funding
A cash account pays 100 percent. Regulation T lets a margin account borrow 50 percent, over a FINRA Rule 4210 floor of 25 percent of market value.
Execution · 8 guides
Execution.
Follow what happens between seeing a quote and getting a fill. Start with a question and work through the explanation at your own pace.
Day and good-til-canceled order conditions
A day order cancels at the 4 p.m. Eastern close. GTC, IOC, FOK and AON differ on how long the order lives and what happens to the unfilled shares.
Market or limit: understand the trade-off
A market order for 1,000 shares at a $3.00 best offer can fill 500 at $3.00 and 500 higher. A limit order fixes price and risks not filling at all.
Partial fills: one order, several executions
A 1,000-share market order can fill 500 at $3.00 and 500 higher. The unfilled remainder is decided by the instruction attached, not by the market.
Quoted at one price, filled at another
A quote is a price for a specific number of shares. Selling 500 shares at a $20.00 bid can print $20.05 or $19.95, a $50 range on a $10,000 sale.
Stop and stop-limit orders behave differently
A stop becomes a market order at the stop price; a stop-limit becomes a limit order. A $3.00 stop with a $2.50 limit will not fill into a $2.20 gap.
T+1: the trade date is not the settlement date
Rule 15c6-1 sets settlement at one business day after the trade, in force since 28 May 2024. A Friday sale settles Monday, and selling early is freeriding.
US day-trading margin rules are in transition
FINRA's intraday margin standard took effect 4 June 2026 and firms can phase in until 20 October 2027. The $25,000 pattern day trader minimum is gone.