Trading & execution

Order Internalization vs Exchange Routing Order internalization vs exchange routing: brokers may fill orders internally at prices competitive with exchanges, but face conflicts of interest that favor their own margins.

Order Queue Priority Rules in Exchange Matching Engines Order queue priority rules on exchanges determine which limit orders fill first—price-time, pro-rata, or price-size—affecting your fill probability and execution speed.

Order Queue Priority: Time-Pro-Rata vs Pure Time How time-priority and pro-rata matching algorithms determine fill probability for limit orders in different markets and exchanges.

Order Routing Logic Decision algorithm for directing orders to trading venues based on liquidity, cost, and speed requirements.

Order Types Instructions to buy or sell securities with specified conditions (price, timing, size). Different types serve different trading needs.

Over-the-Day Execution An execution strategy that distributes a large order across the full trading session to minimise intraday concentration risk and market impact.

Overnight Financing Cost in CFD and Margin Trading How overnight financing costs on CFDs and margin positions compound over time, calculated daily by brokers based on leverage and interest rates.

Overnight Gap Price jump between market close and next day open, typically driven by overnight news.

Partial Fill Execution of only a portion of an order when full immediate execution is unavailable.

Partial Fill in Order Execution What is a partial fill in trading: when only part of your order executes, how brokers handle the remainder, and cost implications.

Participation of Volume Algorithm An execution algorithm that buys or sells a target fraction of market volume to disguise order size and limit adverse price movement.

Participation Rate Order Order type that trades automatically at a fraction of market volume to minimize market impact.

Pattern day trader A pattern day trader (PDT) is a trader who makes four or more day trades (buy and sell of the same security within a single day) in a rolling five business day period. PDTs are subject to SEC rules requiring a minimum $25,000 account balance and margin restrictions.

Payment for order flow Payment for order flow (PFOF) is when a broker sells its customer orders to a market maker (typically in exchange for better prices or rebates). The broker receives payment; the customer may receive modest price improvement, but the arrangement creates potential conflicts of interest.

Payment for Order Flow Explained How brokers earn revenue by selling retail orders to market makers, why it's controversial, and what it means for the prices retail traders receive.

Payment for Order Flow: Cost to Retail Traders Payment for order flow arrangements route retail orders to market makers who pay brokers for the order, potentially resulting in inferior execution prices for retail traders.

Peg order A peg order is a limit order that automatically adjusts its price to maintain a fixed offset from a reference price (typically the bid or ask). The limit price moves with the market.

Peg Order Order that automatically adjusts its limit price based on a reference price, such as the national best bid or ask.

Pegged Order (Exchange) Order price automatically tracks bid-ask spread, moving in tandem with market quotes.

Pegged Order Types Pegged order types automatically track the best bid or ask price (NBBO), adjusting in real time—including midpoint-peg, primary-peg, and market-peg—to reduce adverse selection and market impact.

Pegged Order Types Compared: Primary, Midpoint, and Market Peg Primary peg anchors to the NBBO; midpoint peg targets the bid-ask midpoint; market peg follows the best price. Compare strategies, execution, and when to use each.

Portfolio Compression and Margin Reduction in Clearing How portfolio compression cycles eliminate redundant derivative contracts at a CCP, shrinking margin requirements and gross notional exposure.

Post-Only Order Type How post-only orders prevent execution as a taker, allowing traders to collect maker rebates or control transaction costs.

Post-Trade Transaction Cost Analysis Systematic measurement of realised execution costs against a benchmark after orders are filled.

Post-Trade Transparency and Reporting Obligations What must be reported after a trade executes—price, size, time, and venue. How deferred waivers work for large trades under MiFID II and Dodd-Frank.

Power Hour in the Stock Market The final trading hour before market close, when volume and volatility surge as institutional traders rebalance and momentum traders pile in.

Pre-Hedging and Conflicts of Interest in Execution Examines the controversial practice of pre-hedging, where a dealer trades ahead of a large client order to protect against adverse price movement, and the regulatory and ethical tensions it creates.

Pre-Market and After-Hours Spread Cost Pre-market and after-hours trading sessions have wider bid-ask spreads than regular market hours, raising execution costs and slowing price discovery.

Pre-Market and After-Hours Trading Risks Pre-market and after-hours trading carry higher risks: wider spreads, thin liquidity, price gaps at market open, and limited price discovery. Understanding these hazards is crucial for retail traders.

Pre-Market Gap Fill Rate How often a stock's pre-market gap closes during the regular trading session, and which stock characteristics predict higher fill rates.

Pre-Market Price Discovery How prices form in thin pre-market sessions through news reactions, earnings releases, and futures arbitrage before the regular-hours open.

Pre-Open Drift Systematic price movement in pre-market trading hours in response to overnight news and earnings surprises.

Pre-Settlement Matching: How Trades Are Confirmed Before Settlement Pre-settlement matching confirms trade details at a repository or central securities depository before funds and shares change hands, stopping settlement failures.

Pre-Trade Analytics Forecasting expected execution cost, market impact, and timing risk before an order is submitted.

Price Improvement Execution of a trade at a price better than the current quoted bid or ask.

Price Improvement in Order Execution What price improvement is, how brokers execute orders better than the NBBO, and how to evaluate whether your broker delivers it.

Price-Time Priority The exchange matching rule that fills better-priced orders first and gives the earliest-arriving orders priority among same-price orders.

Primary Peg Order An order type that automatically adjusts its limit price to match the same-side best bid or offer, maintaining price protection without crossing the spread.

Prime broker A prime broker is a full-service financial institution that provides clearing, settlement, financing (margin and securities lending), and other services to large traders and hedge funds. They enable institutions to trade large sizes with leverage.

Principal Trading vs Agency Trading The distinction between a broker risking its own capital to fill orders versus acting purely as an intermediary without taking inventory risk.

Quadruple Witching The simultaneous expiration of stock options, index options, stock index futures, and single-stock futures on the third Friday of March, June, September, and December.

Quarter-End Effect Unusual trading patterns and price movements that occur around quarterly reporting deadlines as investors reposition and funds execute strategies.

Queue Priority in a Limit Order Book Queue priority in a limit order book determines which resting orders fill first. Price-time, pro-rata, and hybrid rules reward early placement or large stakes differently.

Realized Spread The spread revenue a market maker actually earns after accounting for adverse price movement between posting a quote and hedging the resulting trade.

Reg NMS Order Protection Rule The SEC rule requiring brokers to execute orders at any venue displaying the best protected bid or ask price.

Reg SHO Close-Out Requirement for Fails to Deliver How SEC Regulation SHO's close-out requirement forces broker-dealers to buy back shares when fails to deliver persist beyond settlement deadlines.

Registered vs Street-Name Settlement The difference between holding securities in your own name versus your broker's street name, and how each affects settlement, voting, and transfers.

Regulatory Trading Fees: SEC and FINRA Charges SEC and FINRA levy regulatory trading fees on stock sales and options trades. Section 31 and FINRA transaction fees are passed to traders and appear on confirmations.

Rehypothecation The practice of brokers reusing client-posted collateral as security for their own borrowing, creating leverage and systemic risk.

Repo Margin Framework How haircuts and collateral valuation work in repurchase agreements, protecting the cash lender against collateral value fluctuations.

Reserve Order An exchange mechanism that displays only a small visible quantity while a hidden reserve portion refreshes as the visible portion is traded.

Retail Order Routing vs Direct Market Access How retail brokers route orders through intermediaries versus direct market access (DMA), affecting execution price, speed, and transparency.

Reversion Risk in Trade Execution Reversion risk describes how temporary price impact from a large trade partially reverses after execution, affecting measured slippage and execution quality assessment.

Rollover Cost in Futures Contracts The bid-ask spreads and price differences incurred when traders close an expiring futures position and open a new one in the next contract month.

Same-Day Affirmation and the Settlement Deadline Same-day affirmation (SDA) requires traders to confirm trade details before end of trading. Learn why it matters for T+1 settlement and how missed deadlines trigger settlement fails.

Schedule-Driven Execution Algorithms that pace order release over time or volume to minimize market impact while achieving a target execution target.

Securities Dematerialization The shift from physical paper certificates to purely electronic book-entry records held at central depositories, underpinning modern settlement systems.

Securities Information Processor The central utility consolidating and disseminating real-time quotes and trade data across US equity markets.

Securities Lending Collateral Schedule The tiered haircut table governing which non-cash collateral a lender accepts and at what valuation in securities lending.

Securities Lending in Short Selling Securities lending in short selling provides the borrowed shares needed to sell short, enforced through locate requirements, borrow fees, and recall risk.