Final answer:
A 'locked-in' trade in NASDAQ System is an electronically executed and reported trade with terms accepted by both buyer and seller, ensuring it is settled and binding.
Step-by-step explanation:
A 'locked-in' trade within the context of the NASDAQ System (Single Book) refers to a trade where all terms and conditions are finalized and accepted by both the buyer and the seller. This defines the essence of a locked-in trade within electronic trading platforms, where after the trade occurs electronically, its details are reported to NASDAQ and sent for clearing to the National Securities Clearing Corporation (NSCC), which handles the post-trade processing. This ensures that the trade is binding and processed for settlement, effectively 'locking in' the obligations of both trade counterparties. Locked-in trades differ greatly from over-the-phone or online negotiated trades or those quoted only in the OTCBB and Pink Sheets, as they are a part of a formalized and regulated exchange process. The NASDAQ operates in a different manner compared to the more traditional open-outcry system of the New York Stock Exchange (NYSE), where trading involves a physical trading floor and exchange members owning 'seats' to trade.