Order execution and trade mechanics
Order types, slippage, requote, partial fill, last-look execution. The boring layer that decides whether your edge survives contact with the broker. Most retail traders ignore this; institutional desks obsess over it.
FIFO (First-In First-Out)
Position-closure rule requiring the oldest opened lots to close first. US FX brokers are FIFO-mandated by NFA.
GFD (Good For Day)
Order time-in-force: expires at session close. Default for intraday-only orders.
GTC (Good Till Cancelled)
Order time-in-force: stays active until filled or manually cancelled. Default for swing-trade limit orders.
Hidden order
Limit order that doesn't display in the public book at all. Sits invisibly waiting for an aggressive market order to find it.
Iceberg order
Large order split into smaller visible chunks. Shows a small piece in the book; replenishes when the visible piece fills.
Last-look execution
Market-maker right to reject an aggressor order at the quoted price within milliseconds of submission. Asymmetric: accepts when market moves in MM's favor, rejects when it moves against.
Limit order
DeepOrder to buy at a maximum price (or sell at a minimum). Fills only at the limit price or better. Trades price certainty for execution certainty.
Liquidation / offsetting
Closing an open position via an opposing trade. The standard way out of any leveraged position.
Margin call
Broker warning that account equity has fallen toward margin requirement. If equity reaches the auto-liquidation threshold, the broker force-closes positions.
Market order
DeepOrder to buy or sell immediately at the best available price. Fills fastest but exposed to slippage in fast markets.
OCO order (One Cancels Other)
DeepPair of orders where filling one automatically cancels the other. Standard wrapper for take-profit + stop-loss on a single position.
Partial fill
Order fills for less than the requested size because counterparty volume at your price is limited. Remainder stays open or cancels.
Requote
Broker rejection of an order at the requested price followed by a new offered price. Common on market-maker brokers in fast markets.
Slippage
DeepDifference between the intended execution price and the actual fill price. Largest hidden cost beyond the spread.
Stop order
DeepOrder that becomes a market order once a trigger price is hit. Used for stop-loss exits and breakout entries.
Stop-hunt
Brief price move that triggers a cluster of resting stop orders then immediately reverses. Done deliberately by liquidity providers or by emergent algorithmic herd behavior.
Take-profit order
Limit order at a planned profit target. Used as the upper bracket in OCO exits.
Trailing stop
DeepStop-loss that dynamically follows price in the profit direction, locking in gains while leaving room for normal pullback.