Glossary · 133 terms
Trading & Execution
All trading & execution terms in the EquitiesAmerica.com glossary — plain-English definitions for American investors.
Access Fee Cap(Rule 610 cap)
The access fee cap is the regulatory ceiling of $0.003 per share (30 cents per 100 shares) that the SEC established under Rule 610 of Regulation NMS, limiting the maximum fee that a trading venue may charge for accessing displayed quotes, with the goal of preventing exchanges from pricing access to their best quotes at levels that would discourage inter-market competition and harm best execution.
Algorithmic Trading(algo trading)
Algorithmic trading refers to the use of computer programs that execute buy and sell orders in financial markets based on a predefined set of rules, such as price thresholds, timing, volume conditions, or mathematical models. In U.S. markets, algorithmic trading now accounts for a substantial share of daily equity volume across NYSE and NASDAQ.
All or None(AON)
An all-or-none (AON) order instructs a broker to execute an order only if the entire quantity can be filled; unlike a fill or kill order, it does not require immediate execution and may remain active until cancelled.
Arrival Price(decision price)
The arrival price is the midpoint of the national best bid and offer at the exact moment a trading order is submitted to the market, serving as the baseline benchmark against which implementation shortfall and execution quality are measured for institutional orders.
Auction Market Reform(opening auction reform)
Auction market reform refers to regulatory and exchange-driven initiatives to improve the transparency, competitiveness, and price discovery efficiency of the opening and closing auctions that determine the official start-of-day and end-of-day reference prices for U.S. listed equity securities, as well as proposals to introduce intraday periodic auctions as an alternative to continuous trading.
Benchmark Slippage(execution slippage)
Benchmark slippage is the difference between the volume-weighted average execution price of a trade and the target benchmark price, expressed in basis points, quantifying how much better or worse an institutional order executed relative to the chosen reference price such as VWAP, TWAP, or arrival price.
Best Execution
Best execution is the regulatory obligation requiring broker-dealers to seek the most favorable terms reasonably available when executing customer orders, considering factors such as price, speed, likelihood of execution, and order size.
Best Execution Obligation(best execution)
The best execution obligation is the legal and regulatory requirement that broker-dealers and investment advisers take reasonable steps to obtain the most favorable terms reasonably available when executing securities orders on behalf of clients, balancing price, speed, likelihood of execution, and other relevant factors.
Block Crossing Network(dark pool crossing network)
A block crossing network is an electronic trading platform that matches large institutional orders against each other anonymously at or near the midpoint of the national best bid and offer, allowing institutions to trade sizable blocks of shares without revealing their interest to the broader market.
Block Trade(block transaction)
A block trade is a large securities transaction, typically defined in U.S. equity markets as involving at least 10,000 shares or a notional value of at least $200,000, that is often executed outside of the open market to minimize market impact and avoid signaling the order to other participants. Block trades are a primary tool of institutional liquidity management.
Bracket Order(OCA bracket)
A bracket order is a three-legged order structure that simultaneously pairs an entry order with a pre-set profit target and a pre-set stop-loss, automatically cancelling the remaining exit leg once either the target or the stop is filled.
Brent Crude(Brent)
Brent Crude is the leading international oil price benchmark, derived from crude oil extracted from the North Sea and used as the reference price for approximately two-thirds of the world's internationally traded oil contracts.
Carry Trade(FX carry trade)
A Carry Trade is a currency trading strategy that borrows in a low-interest-rate currency and invests the proceeds in a higher-yielding currency, profiting from the interest rate differential as long as exchange rate movements do not exceed the yield advantage.
Central Counterparty Clearing(CCP)
Central counterparty clearing (CCP clearing) is the process by which a clearinghouse interposes itself as the buyer to every seller and seller to every buyer in a financial transaction, centralizing counterparty risk management, enabling multilateral netting of obligations, and providing a structured default management process.
Clearinghouse(central counterparty)
A clearinghouse is a financial intermediary that interposes itself between the buyer and seller of a financial contract, becoming the buyer to every seller and the seller to every buyer, thereby eliminating bilateral counterparty risk and ensuring contract performance through margin requirements and default management procedures.
Close-Out Netting(ISDA close-out netting)
Close-out netting is a legal mechanism that terminates all outstanding derivatives contracts between two counterparties upon the default of one, calculates the net mark-to-market value of all terminated contracts, and requires only a single net payment — eliminating the risk that a bankruptcy administrator could selectively enforce contracts favorable to the defaulted party.
Closing Auction(market close auction)
The closing auction is an end-of-day matching process run by a stock exchange that aggregates all buy and sell orders submitted during the day for execution at a single official closing price, establishing the widely used 4:00 PM closing price for US equities.
Co-Location(colocation)
Co-location (or colocation) is a service offered by stock exchanges and trading venues that allows trading firms to place their servers physically inside the exchange's data center, reducing the time — often to microseconds — it takes for their order messages to reach the exchange's matching engine. Co-location is a foundational infrastructure component of high-frequency and algorithmic trading in U.S. equity markets.
Co-Location Services(colocation)
Co-location services are commercial arrangements offered by stock exchanges that allow market participants to house their trading servers in the same physical data center as the exchange matching engine, reducing the physical distance that electronic signals must travel and thereby minimizing the network latency that determines order submission and cancellation speed in competitive electronic markets.
Commodity Index(commodity benchmark)
A Commodity Index is a benchmark that tracks the price performance of a basket of commodity futures contracts, providing a single number that represents the aggregate return from exposure to a diversified set of physical commodities including energy, metals, and agricultural products.
Conditional Order(contingent order)
A conditional order is an advanced order instruction that is only submitted to the market or activated when a defined set of criteria — such as a price threshold, a time condition, or the execution of another order — is first satisfied.
Consolidated Tape(tape)
The Consolidated Tape is the real-time data feed that reports last-sale information — price, volume, and exchange — for every trade executed in US-listed equity securities across all registered trading venues.
Contagion (Financial)
Financial contagion is the spread of financial distress, market instability, or crisis conditions from one market, institution, or country to others through direct financial linkages, common exposures, or investor behavior, often affecting entities with no fundamental connection to the original source of stress.
Continuous Net Settlement(CNS)
Continuous Net Settlement (CNS) is the NSCC's primary settlement system that continuously nets and processes securities transactions on a rolling basis, calculating each participant's net security and cash obligations across all unsettled trades to minimize the physical transfer of securities required for settlement.
Copper (as Economic Indicator)(Doctor Copper)
Copper is a base metal whose price is widely used as a real-time leading indicator of global economic health, reflecting demand from construction, manufacturing, and infrastructure spending, earning it the informal title of the metal with a PhD in economics.
Counterparty Risk(default risk)
Counterparty risk is the probability that the other party to a financial contract — a derivatives counterparty, lending counterparty, or clearing member — will fail to fulfill its obligations, potentially causing financial loss to the party that performed as required.
D-Limit Order (IEX)(Discretionary Limit order IEX)
The D-Limit order is a proprietary order type offered exclusively on IEX that combines a displayed limit order with a discretionary price-adjustment mechanism: when IEX's Signal (the crumbling quote indicator) detects that the national best bid or offer is about to move adversely against a resting D-Limit order, the exchange automatically reprices the order downward by one tick before incoming marketable orders can execute against it.
Dark Pool(alternative trading system)
A dark pool is a private electronic trading venue where institutional investors can buy and sell large blocks of securities away from public exchanges, with order information withheld from the broader market until after execution.
Dark Pool Regulation(ATS regulation)
Dark pool regulation refers to the body of U.S. Securities and Exchange Commission rules and FINRA oversight requirements governing alternative trading systems that execute equity transactions away from lit public exchanges, with the primary goals of ensuring fair access, preventing information leakage, and requiring adequate post-trade transparency.
Day Order(day limit order)
A day order is a buy or sell instruction that expires automatically at the end of the regular trading session on the day it is entered, if it has not been executed by that time.
Decimal Pricing (Decimalization)(decimalization)
Decimalization refers to the 2001 transition of U.S. equity markets from quoting and trading stock prices in fractions — historically as small as one-eighth or one-sixteenth of a dollar — to quoting in decimal increments of one cent, a change that dramatically narrowed bid-ask spreads, reduced explicit transaction costs for investors, and fundamentally reshaped the economics of market-making.
Direct Market Access(DMA)
Direct market access (DMA) is a service provided by broker-dealers that allows institutional clients to submit orders directly to an exchange or trading venue's order book without the broker manually handling or routing the order, giving the client speed, control, and transparency over their executions.
Displayed Order(lit order)
A displayed order is a buy or sell instruction submitted to a trading venue whose price and size are published to the public market data feeds, contributing directly to the national best bid and offer and serving as the foundation of pre-trade price transparency in U.S. equity markets.
Effective Spread(effective half-spread)
The effective spread is a transaction cost measure that captures the actual round-trip cost of a trade by comparing the execution price to the midpoint of the national best bid and offer at the time of execution, reflecting the true price paid or received relative to the fair value midpoint.
Efficient Price(efficient market price)
An Efficient Price is a market price that fully and correctly reflects all relevant available information about an asset's fundamental value, such that no investor can consistently earn risk-adjusted excess returns by trading on that information alone.
Exchange-Traded Note(ETN)
An Exchange-Traded Note (ETN) is an unsecured debt obligation issued by a financial institution that trades on a stock exchange and promises to pay the return of a specific index or benchmark, minus fees, at maturity.
Extended Hours Trading(after-hours trading)
Extended hours trading refers to the buying and selling of U.S. exchange-listed securities outside the standard 9:30 a.m. to 4:00 p.m. Eastern Time regular session, encompassing both the pre-market period in the morning and the after-hours period in the evening.
Failure to Deliver(FTD)
A failure to deliver (FTD) occurs when one party to a securities transaction does not deliver the required securities or cash by the settlement date, creating an open obligation that must be resolved under rules established by the SEC and the broker-dealer community.
Fill or Kill(FOK)
A fill or kill (FOK) order requires that the entire order be executed immediately and in full; if the order cannot be completely filled at once, it is cancelled outright with no partial execution permitted.
Flight to Liquidity
Flight to liquidity is the tendency of investors during periods of market stress to shift holdings from less-liquid assets into highly liquid instruments — such as on-the-run US Treasuries or money market funds — even when the less-liquid assets carry equivalent credit quality, reflecting the premium investors place on the ability to transact immediately at low cost.
Flight to Quality
Flight to quality is the rapid reallocation of investment capital from higher-risk, higher-yield assets into lower-risk, lower-yield assets — most commonly US Treasury securities — during periods of financial stress, crisis, or acute uncertainty.
Forex Market(FX market)
The Forex (Foreign Exchange) Market is the global decentralized marketplace where currencies are traded against each other, operating 24 hours a day across major financial centers and constituting the largest and most liquid financial market in the world by daily trading volume.
Frequent Batch Auctions(batch auctions)
Frequent batch auctions are a proposed alternative to continuous limit order book trading in which incoming buy and sell orders are accumulated over brief, regular intervals — typically between 100 milliseconds and one second — and then matched simultaneously at a single clearing price, eliminating the first-mover advantage that governs continuous markets and potentially reducing the profitability of pure latency-based trading strategies.
Gold (as Investment)(gold bullion)
Gold as an investment asset is a non-income-producing commodity that investors hold for its properties as a store of value, inflation hedge, safe-haven asset during periods of financial stress, and portfolio diversifier, accessed through physical bullion, ETFs, futures, or mining equities.
Good-Till-Cancelled Order(GTC order)
A good-till-cancelled (GTC) order is a buy or sell instruction that remains active until it is either executed or explicitly cancelled by the investor, as opposed to expiring at the end of the trading day.
Haircut (Collateral)
A haircut is the percentage reduction applied to the market value of collateral when calculating how much credit or margin it provides, reflecting the risk that the collateral could decline in value during the time it takes to liquidate it if the borrower defaults.
Henry Hub Natural Gas(Henry Hub)
Henry Hub Natural Gas refers to the price of natural gas at the Henry Hub pipeline interconnection in Louisiana, which serves as the primary US natural gas pricing benchmark, with futures contracts traded on the NYMEX priced in US dollars per million British thermal units (MMBtu).
High-Frequency Trading(HFT)
High-frequency trading (HFT) is a form of algorithmic trading characterized by extremely high order submission rates, very short holding periods measured in microseconds to milliseconds, and the use of co-located servers to minimize latency. HFT firms are among the most active participants in U.S. equity markets.
Iceberg Order(reserve order)
An iceberg order is a large institutional order that is divided into smaller visible tranches, with only a fraction of the total quantity displayed on the order book at any given time, concealing the full size of the intended trade from other market participants.
Implementation Shortfall(IS)
Implementation shortfall is a transaction cost measurement framework that quantifies the difference between the theoretical return of a trading decision — as if executed at the price when the decision was made — and the actual return achieved after accounting for all execution costs including commissions, market impact, and slippage. It is the most comprehensive measure of total trading cost used by institutional investors.
Implementation Shortfall Algorithm(IS algorithm)
An implementation shortfall algorithm is an algorithmic execution strategy that optimizes the trade-off between market impact cost and timing risk, front-loading execution to minimize the gap between the decision price and the average execution price, particularly when the trading signal is time-sensitive.
Informed Trading
Informed Trading refers to transactions executed by investors who possess a genuine informational edge — either through superior fundamental research, proprietary models, or in illegal cases, material non-public information — that gives them an expectation of profit based on knowing more than the market consensus.
Initial Margin vs Variation Margin(IM)
Initial margin is collateral posted upfront to cover potential future losses on a derivatives or leveraged position, while variation margin is collateral paid daily to reflect the actual mark-to-market gains and losses on open positions — together they form the two-layer margin system used by clearinghouses and prime brokers to manage counterparty risk.
Institutional Order(institutional order flow)
An institutional order is a securities transaction instruction originating from a professional investment organization such as a mutual fund, pension fund, hedge fund, or asset manager, typically involving large share quantities that require specialized execution strategies to minimize market impact and transaction costs.
Internalization(order internalization)
Internalization is the practice by which a broker-dealer executes a customer order against its own inventory or through an affiliated market maker rather than routing the order to a national securities exchange, allowing the firm to capture the spread while potentially offering price improvement to the customer.
Inverted Venue(inverted exchange)
An inverted venue is a stock exchange or trading platform that pays a rebate to order flow that removes liquidity (takers) and charges a fee to order flow that provides resting liquidity (makers), reversing the standard maker-taker fee structure.
Latency (Market)(trading latency)
Market latency is the elapsed time between when a trading event — such as a quote update, order submission, trade execution, or market data dissemination — originates at one point in the trading infrastructure and when it is received, processed, or acted upon at another point, a measure that has become critically important as electronic trading has compressed meaningful speed differences to the microsecond and nanosecond scale.
Latency Arbitrage(speed arbitrage)
Latency arbitrage is a trading strategy that exploits the time delay — often measured in microseconds — between when price information becomes available to one market participant and when it reaches another, allowing faster participants to trade on stale quotes posted by slower counterparties. It is most commonly associated with high-frequency trading firms in U.S. equity markets.
Lit Market(displayed market)
A lit market is a trading venue where orders and their associated prices are publicly displayed to all market participants in real time, providing full pre-trade transparency as required by U.S. Securities and Exchange Commission regulations governing national securities exchanges.
Locate (Short Selling)(short locate)
A locate is a broker-dealer confirmation that a sufficient quantity of a specific security is available to borrow before executing a short sale, as required by SEC Regulation SHO to prevent the creation of naked short positions in most circumstances.
Maker-Taker Pricing(maker-taker)
Maker-taker pricing is a fee structure used by most US stock exchanges in which participants who post resting limit orders (makers) receive a rebate, while participants who remove that liquidity with incoming orders (takers) pay a fee.
Maker-Taker vs Taker-Maker(maker-taker fee model)
Maker-taker and taker-maker are the two principal fee structures used by U.S. stock exchanges to price access to their liquidity: in a maker-taker model, exchanges pay rebates to limit order providers (makers) and charge fees to marketable order takers, while taker-maker models invert this, charging makers and paying takers, with each structure creating different incentives for order routing and broker behavior.
Margin Account(margin brokerage account)
A margin account is a brokerage account in which the broker lends the investor a portion of the purchase price of securities, allowing the investor to buy more than they could with their own capital alone, using the securities in the account as collateral.
Margin Call
A margin call is a demand from a broker that an investor deposit additional funds or securities into a margin account to bring the account's equity back above the required maintenance margin level after market losses have reduced it below the minimum threshold.
Market Data Fee(data fees)
A market data fee is a charge levied by a stock exchange for access to its proprietary real-time quote and trade data, including depth-of-book information, direct data feeds, and co-location services that transmit market information faster than consolidated SIP feeds.
Market Data Revenue(exchange data fees)
Market data revenue refers to the income that U.S. stock exchanges earn by licensing access to the real-time and historical price, quote, and trade data generated by trading activity on their venues, which has grown into a multi-billion-dollar annual revenue stream that has attracted significant regulatory scrutiny over exchange pricing power and data governance.
Market Impact(price impact)
Market impact is the adverse effect that a large trading order has on the price of a security as it is executed, reflecting the price movement caused by the act of trading itself rather than by independent market forces. Minimizing market impact is a central objective of institutional execution strategy in U.S. equity markets.
Market Impact Cost(price impact)
Market impact cost is the adverse price movement caused by the act of executing a trade, representing the portion of total transaction cost attributable to the order's own influence on the market price rather than to pre-existing spread or fees.
Market Microstructure
Market Microstructure is the study of the processes and mechanisms by which financial securities are traded, covering the formation of prices, the role of market makers and intermediaries, the impact of order types, and the effects of trading rules on transaction costs and price efficiency.
Microwave Networks (Trading)(microwave trading)
Microwave networks in trading are proprietary wireless transmission infrastructures that high-frequency trading firms and financial data providers have built to transmit market data and order signals between major financial center data centers — primarily New York and Chicago — faster than conventional fiber optic cables, exploiting the fact that microwave signals travel through air at speeds closer to the speed of light than signals through glass fiber.
Midpoint Match(midpoint execution)
A midpoint match is the execution of a buy order and a sell order at the exact midpoint of the national best bid and offer, allowing both parties to split the bid-ask spread equally and achieve an execution price better than either the displayed bid or the displayed offer.
Midpoint Order(midpoint peg order)
A midpoint order is a non-displayed order type that executes at the midpoint of the national best bid and offer, allowing both buyer and seller to achieve price improvement by splitting the bid-ask spread rather than paying the full spread at the posted quotes.
National Best Bid and Offer (NBBO)(NBBO)
The National Best Bid and Offer (NBBO) is the highest available buy price and the lowest available sell price for a security across all registered US exchanges and market centers at any given moment.
Netting(payment netting)
Netting is the process of combining multiple offsetting financial obligations between two or more parties into a single net obligation, reducing the gross notional amount of transactions that must be settled and lowering both counterparty risk and funding requirements.
Noise Trading
Noise Trading refers to buying and selling securities based on irrelevant information, sentiment, rumors, or cognitive biases rather than fundamental value analysis, introducing price volatility and deviations from efficient prices that can persist when noise traders are numerous enough to represent a significant portion of market activity.
Non-Displayed Order(hidden order)
A non-displayed order is a trading instruction whose price and size are withheld from public market data feeds, allowing participants to maintain a presence in the market without revealing their full trading intentions, commonly used by institutional investors seeking to minimize information leakage.
Odd Lot(odd-lot order)
An odd lot is a securities order or holding consisting of fewer than 100 shares of a stock, which is the standard unit of trading (a round lot) in U.S. equity markets. Odd lots arise frequently in the context of dividend reinvestment plans, fractional share investing, and certain corporate actions.
Odd Lot Information(odd lot quotes)
Odd lot information refers to data on equity orders and transactions involving fewer than 100 shares — the threshold below which an order is classified as an odd lot under traditional U.S. exchange conventions — which was historically excluded from the national best bid and offer calculation but has grown in significance as retail participation has increased and share prices have risen.
Odd Lot Transparency(odd-lot quotes)
Odd lot transparency refers to the inclusion of orders and quotes involving fewer than 100 shares (odd lots) in consolidated market data feeds, a reform that became effective in 2023 under updated SEC market data rules.
One-Cancels-Other Order(OCO order)
A one-cancels-other order is a paired order instruction in which two separate orders are linked so that when one is executed or triggered, the other is automatically cancelled, allowing a trader to simultaneously hold both a profit-taking target and a loss-limiting exit on the same position.
Opening Auction(opening cross)
The opening auction is the price-discovery mechanism run by a stock exchange at the start of each trading day that aggregates pre-market orders and executes them at a single equilibrium price, establishing the official opening price for each listed security.
Order Protection Rule(Rule 611)
The Order Protection Rule, established under SEC Regulation NMS Rule 611, requires trading venues to route equity orders to the market center displaying the best available price rather than executing against an inferior quote on their own platform.
Participation Rate Algorithm(POV algorithm)
A participation rate algorithm is an algorithmic execution strategy that trades a target security at a fixed percentage of real-time market volume, automatically adjusting the rate of order submission to match the rhythm of market activity and control the order's footprint relative to overall trading.
Payment for Order Flow(PFOF)
Payment for order flow (PFOF) is the practice by which a retail broker receives compensation from a market maker or trading firm in exchange for routing the broker's customer orders to that firm for execution.
Payment for Order Flow Debate(PFOF)
The payment for order flow debate centers on whether broker-dealers should be permitted to receive compensation from wholesale market makers in exchange for routing retail customer equity and options orders to those market makers for execution, with critics arguing the practice creates conflicts of interest that compromise execution quality and supporters contending it funds commission-free trading while still delivering competitive fills.
Pegged Order(peg order)
A pegged order is a dynamic limit order whose price is automatically adjusted to track a reference benchmark — most commonly the national best bid, national best offer, or midpoint — so that the order remains competitive without requiring manual repricing by the submitting party.
Permanent Price Impact(information-driven price impact)
Permanent price impact is the portion of the price movement caused by a trade that does not revert after execution is complete, representing the market's lasting revision of a security's value based on the information content it inferred from the order flow.
Portfolio Margin(risk-based margin)
Portfolio margin is a risk-based margin methodology approved by FINRA and the SEC that calculates margin requirements based on the net risk of an entire portfolio rather than applying fixed percentage requirements to each position individually, typically enabling qualified investors to carry larger positions with less margin capital than under standard Regulation T rules.
Pre-Market Session(pre-market trading)
The pre-market session is the extended trading period that occurs before the official 9:30 a.m. Eastern Time open of U.S. equity markets, typically running from 4:00 a.m. ET, during which investors can trade securities at prices that reflect overnight news and events.
Price Discovery
Price Discovery is the continuous market process through which buyers and sellers interact to establish an asset's current price, incorporating all available information about supply, demand, future expectations, and risk into the prevailing market quote at any given moment.
Price Improvement(execution price improvement)
Price improvement occurs when a trade executes at a price better than the national best bid or offer at the time of the order, meaning a buyer pays less than the best available offer or a seller receives more than the best available bid, representing a direct saving for the investor.
Price-Time Priority(FIFO matching)
Price-time priority is the foundational order matching algorithm used by all major U.S. equity exchanges, in which incoming marketable orders are filled against resting limit orders by first selecting the best available price (highest bid or lowest offer) and then, among all resting orders at that best price, selecting the one that arrived earliest in time, ensuring that competitive price improvement is rewarded and that early commitment to a price is honored.
Proprietary Data Feed(direct feed)
A proprietary data feed is a direct, low-latency market data connection sold by an individual stock exchange to subscribers, delivering real-time quotes, trades, order book depth, and auction information with significantly lower latency and greater granularity than the consolidated Securities Information Processor feed, giving subscribing firms a measurable speed and information advantage over those relying solely on the public SIP.
Queue Priority(order queue priority)
Queue priority is the ranking system that determines the sequence in which resting limit orders at the same price level on an exchange order book are matched against incoming marketable orders, with the most common U.S. equity market convention being price-time priority — first ranked by best price and then, among orders at the same price, by time of arrival.
Quoted Spread(bid-ask spread)
The quoted spread is the difference between the best publicly displayed offer price and the best publicly displayed bid price for a security at a given moment, representing the explicit cost of immediately buying and selling in the public market and serving as the most visible indicator of market liquidity.
Realized Spread(realized half-spread)
The realized spread is a market microstructure measure of liquidity provider profitability that calculates the spread revenue earned by a market maker net of the adverse price movement that occurs after a trade, isolating the compensation for providing liquidity from the cost of bearing adverse selection.
Rebate Arbitrage(rebate capture)
Rebate arbitrage is a trading strategy that seeks to capture exchange liquidity rebates as a primary or supplementary profit source by posting limit orders designed to earn the maker rebate upon execution, sometimes engaging in strategies where the rebate income exceeds the expected loss from adverse price movement, effectively treating exchange fee structures as a component of the return calculation rather than a pure transaction cost.
Regulation NMS(Reg NMS)
Regulation NMS (National Market System) is a set of SEC rules adopted in 2005 that governs how U.S. equity markets are structured, requiring trade-throughs to be prevented and establishing a framework for fair access to market data and order execution across exchanges.
Regulation T(Reg T)
Regulation T is a Federal Reserve Board rule that governs the extension of credit by broker-dealers to customers for the purpose of purchasing securities, establishing the initial margin requirement — currently 50 percent — that investors must deposit when buying securities on margin.
Retail Execution Quality(order execution quality)
Retail execution quality refers to the overall standard of trade execution received by individual investors when their stock orders are filled, encompassing metrics such as effective spread, price improvement, fill rate, speed of execution, and the extent to which realized execution prices compare favorably to the national best bid and offer at the time of order submission.
Retail Liquidity Program(RLP)
A Retail Liquidity Program (RLP) is an exchange mechanism that allows designated market participants to offer price improvement to verified retail order flow, typically at prices inside the prevailing NBBO, in exchange for a lower access fee.
Retail Order(retail order flow)
A retail order is a securities transaction instruction originating from an individual investor rather than a professional trading firm or institution, typically characterized by small share quantities, uninformed trading motivation, and routing to wholesale market makers under U.S. equity market structure.
Risk-On/Risk-Off(RORO)
Risk-On/Risk-Off (RORO) describes the broad market dynamic where investor sentiment swings between periods of risk appetite (risk-on), during which capital flows into equities, high-yield debt, commodities, and emerging markets, and periods of risk aversion (risk-off), during which capital rotates into Treasuries, gold, the US dollar, and other perceived safe havens.
Roll Yield(roll return)
Roll Yield is the gain or loss generated when a futures investor rolls an expiring contract into a new contract at a later expiration date, arising from the difference in price between the two contracts — positive in backwardated markets and negative (a drag) in contango markets.
Round Lot(round lot order)
A round lot is the standard trading unit for U.S. equity markets, consisting of 100 shares or any multiple of 100 shares, and historically represents the baseline order size that exchanges and market makers have been designed to handle in a standardized way.
Round Lot Definition Change(round lot reform)
The round lot definition change is an SEC regulatory reform finalized in 2023 that modernizes the longstanding convention of treating 100 shares as the standard trading unit for all U.S. equity securities, replacing it with a tiered system in which the round lot size scales with share price to ensure that the national best bid and offer reflects prices that are practically accessible to retail investors.
Securities Information Processor(SIP)
A Securities Information Processor (SIP) is a data aggregation system that collects real-time quote and trade information from all US equity exchanges and disseminates a consolidated feed of best bids, best offers, and last-sale prices to the market.
Securities Lending(stock lending)
Securities lending is the temporary transfer of securities by an owner (the lender) to a borrower — typically a broker-dealer or hedge fund — in exchange for collateral and a lending fee, enabling the borrower to use the securities for purposes such as facilitating short sales or satisfying delivery obligations.
Short Selling(shorting)
Short selling is an investment strategy in which an investor borrows shares of a security and sells them with the expectation of repurchasing them later at a lower price, profiting from the difference if the price declines.
Silver (as Investment)(XAG)
Silver as an investment asset is a precious metal that combines the properties of a monetary store of value and a safe-haven asset with substantial industrial demand, making its price driven by a unique blend of financial sentiment and real economic activity.
SIP Latency(consolidated tape latency)
SIP latency refers to the delay between when a quote or trade event occurs on a U.S. stock exchange and when that event is reflected in the consolidated national market system feed produced by the Securities Information Processor, a gap that can range from tens of microseconds to several milliseconds and is commercially exploited by firms with access to faster proprietary exchange data feeds.
Slippage(price slippage)
Slippage is the difference between the expected price of a trade at the time an order is submitted and the actual price at which the order is executed, arising from market movement between order submission and execution, bid-ask spreads, or insufficient liquidity at the desired price level. Slippage can be positive or negative and is a routine consideration in U.S. equity trading.
Smart Order Routing(SOR)
Smart order routing (SOR) is an automated process used by broker-dealers and trading systems to analyze available liquidity across multiple trading venues and route an order to the venue or combination of venues that offers the best available price, minimizing execution cost for the client. SOR is a core component of best-execution compliance in U.S. fragmented equity markets.
Speed Bump (IEX)(IEX delay)
The IEX speed bump is a 350-microsecond intentional signal delay — implemented using approximately 38 miles of coiled fiber optic cable — that Investors Exchange (IEX) requires all incoming and outgoing messages to traverse before interacting with its matching engine, designed to neutralize the latency advantages that co-located high-frequency traders would otherwise hold over longer-term investors.
Spot Price vs Futures Price(spot vs forward)
The Spot Price is the current market price for immediate delivery of a commodity or financial instrument, while the Futures Price is the agreed-upon price for delivery at a specified future date, with the relationship between the two revealing market expectations about supply, demand, storage costs, and carry.
Stop-Loss Order(stop order)
A stop-loss order is an instruction placed with a broker to sell a security automatically once its price falls to a specified level, limiting the investor's potential loss on the position.
Storage Cost(carry cost)
Storage Cost in commodity markets is the expense of physically holding an inventory of a commodity over time — including warehousing or tank fees, insurance, financing charges, and any handling or quality deterioration — which influences the relationship between spot and futures prices.
Sub-Penny Pricing(sub-penny execution)
Sub-penny pricing refers to the practice of executing or quoting equity trades at price increments smaller than one cent — such as $0.001 or fractions thereof — which is prohibited for displayed quotes on U.S. exchanges under SEC Rule 612 but is permitted in certain off-exchange execution contexts, creating an asymmetry that market makers use to gain queue priority without publicly improving displayed prices.
Systemic Risk Indicator(systemic risk measure)
A systemic risk indicator is a quantitative measure designed to detect rising vulnerability in the financial system as a whole — including interconnectedness among institutions, leverage, liquidity stress, and asset price misalignments — providing early warning of conditions that could lead to financial crises.
T+1 Settlement(T+1)
T+1 Settlement means that securities transactions must be fully settled — with securities delivered to the buyer and cash delivered to the seller — within one business day after the trade date, a standard the United States adopted in May 2024 after transitioning from a T+2 cycle.
Temporary Price Impact(transient price impact)
Temporary price impact is the portion of trade-induced price movement that reverts after execution is complete, reflecting the mechanical displacement of the order book by liquidity demand rather than any lasting revision of the market's estimate of a security's value.
Tick Size Pilot Program(tick size pilot)
The Tick Size Pilot Program was a two-year SEC-mandated study conducted from October 2016 to September 2018 that tested whether widening the minimum price increment to five cents for a selected group of smaller-capitalization U.S. stocks would improve liquidity, analyst coverage, and market quality compared to the standard one-cent tick size.
Time Priority(first-in-first-out priority)
Time priority is the secondary order matching rule in U.S. equity markets that governs the sequence of execution among limit orders posted at the same price level, awarding execution precedence to the order that was submitted to the exchange earliest in time, thereby rewarding market participants who are first to commit capital at a given price.
Time-Weighted Average Price(TWAP)
Time-Weighted Average Price (TWAP) is both a benchmark price calculated as the arithmetic average of a security's price over a defined time interval and an algorithmic execution strategy that aims to execute a large order evenly across that interval to match the benchmark. TWAP is widely used by institutional investors in U.S. equity markets to reduce market impact.
Trailing Stop(trailing stop-loss)
A trailing stop is a dynamic stop-loss order that moves in lockstep with a rising security price by a fixed dollar amount or percentage, locking in gains while still protecting against significant reversals.
Transaction Cost Analysis(TCA)
Transaction cost analysis (TCA) is the systematic measurement and evaluation of all costs associated with executing securities trades, comparing actual execution prices against relevant benchmarks to assess execution quality, optimize trading strategies, and fulfill regulatory best execution obligations.
Transaction Fee Pilot(fee pilot)
The Transaction Fee Pilot was an SEC-proposed program, approved in December 2018 but subsequently vacated by a federal appeals court, that would have tested whether reducing or eliminating exchange access fees and rebates affected order routing behavior, execution quality, and market liquidity by randomly assigning a sample of U.S. equity securities into test buckets subject to different fee constraints.
TWAP Algorithm(time-weighted average price algorithm)
A TWAP (Time-Weighted Average Price) algorithm is an algorithmic execution strategy that divides a parent order into equal-sized child orders and distributes them uniformly across a defined time window, aiming to achieve an average execution price close to the simple time-average of market prices over that period.
USD Index (DXY)(DXY)
The US Dollar Index (DXY) is a measure of the value of the US dollar relative to a basket of six major foreign currencies — the Euro, Japanese Yen, British Pound, Canadian Dollar, Swedish Krona, and Swiss Franc — with the Euro receiving the heaviest weighting.
Volume Clock(trade time clock)
A volume clock is a conceptual framework for measuring the passage of time in financial markets using the cumulative trading volume transacted rather than calendar time, capturing the idea that market events and price changes are more closely related to activity than to the passage of clock minutes.
VWAP Algorithm(volume-weighted average price algorithm)
A VWAP (Volume-Weighted Average Price) algorithm is an algorithmic execution strategy that distributes a parent order across the trading day in proportion to predicted trading volume, aiming to achieve an average execution price close to the day's volume-weighted average price, the most widely used institutional execution benchmark in U.S. equity markets.
Wholesaler(wholesale market maker)
A wholesaler, in the context of U.S. equity market microstructure, is a large broker-dealer or market-making firm that pays retail brokerage firms for the right to execute their customers' orders, profiting from the bid-ask spread while providing price improvement relative to the national best bid and offer.
WTI Crude Oil(West Texas Intermediate)
West Texas Intermediate (WTI) Crude Oil is a light, sweet crude oil grade produced primarily in the United States that serves as the principal North American oil benchmark, with prices quoted in US dollars per barrel and futures contracts traded on the New York Mercantile Exchange (NYMEX).