When an institutional investor instructs a broker-dealer to trade, the order ticket must convey far more than simply 'buy' or 'sell'. In institutional markets, every trade instruction is characterized by a rich matrix of execution attributes that dictate price sensitivity, market participation style, venue routing behavior, and temporal lifespan. These attributes are formally codified through Order Types, Time-in-Force (TIF) instructions, and algorithmic execution benchmarks.
At the foundational level, standard order types establish the pricing constraints under which a broker or algorithm may execute. A Market Order (FIX Tag 40=1) prioritizes immediate execution certainty over price, aggressively taking whatever liquidity exists on the public order books. A Limit Order (FIX Tag 40=2) guarantees that execution will only occur at the specified limit price or better, prioritizing price protection over execution certainty. In institutional block trading, however, simple market and limit orders are often too blunt. Desks utilize advanced Pegged Orders (Tag 40=P) that dynamically track the consolidated National Best Bid/Offer (NBBO) or float at the midpoint between the bid and offer in dark pools to capture substantial half-spread cost savings.
Time-in-Force instructions (FIX Tag 59) establish the temporal boundaries of the order. A standard Day Order (Tag 59=0) remains active until the closing bell of the local trading session, automatically expiring if unfilled. Immediate or Cancel (IOC / Tag 59=3) orders demand that any available shares at the venue be executed instantaneously upon arrival, with any unexecuted balance immediately cancelled back to the client. Fill or Kill (FOK / Tag 59=4) orders require the entire order quantity to be executed immediately in full; if full size cannot be satisfied, the entire order is rejected. Good 'Til Date (GTD / Tag 59=6) orders persist across sessions until an explicit expiration timestamp.
At Atlantic Horizon Securities, the sales trading desk configures bespoke algorithmic parameters—such as Volume-Weighted Average Price (VWAP), Time-Weighted Average Price (TWAP), and Percentage of Volume (POV)—translating complex client investment objectives into precise machine-readable FIX parameters.