Execution of Portfolio Decisions INTRODUCTION Three elements of investment process are securities research, portfolio management and securities trading Duties of a portfolio manager includes: • Effective communication with traders • • Ability to evaluate the quality of the execution services Performance of fiduciary responsibility THE CONTEXT OF TRADING: MARKET MICROSTRUCTURE The portfolio manager needs to be familiar with market microstructure: the market structures and price The portfolio manager needs to be familiar with market microstructure: the market structures and processes that affect how trades are executed (represented by trade prices and volumes) 2.1 Order Types Following are the two major types of orders that traders use: Market Order A market order is an instruction to execute an order promptly in the public market at the best price available A market order: • Emphasizes immediacy of execution • Bears some degree of price uncertainty (uncertainty about the price at which the order will be executed) NOTE: In today’s market, most market orders are effectively automated • A variation of the market order designed to give the agent greater discretion than a simple market order ‘Not held’ means the broker is not required to trade at any specific price or in any specific time interval, as would be required with a simple market order Participate (do not initiate) order • A variant of the market-not-held order in which a broker waits for and responds to initiatives of more active traders, in the hope of capturing a better price Best efforts order • This type of order gives the trader’s agent even more discretion to work the order Undisclosed limit order/reserve/hidden/iceberg order • This is a limit order that includes an instruction not to show more than some maximum quantity of the unfilled order Market on open order Limit Order A limit order is an instruction to trade at a price that is at least as good as the limit price specified in the order For buy orders, the trade price must not exceed the limit price, and for sell orders, the trade price must be at least as high as the limit price A limit order: • Emphasizes price • Has execution uncertainty NOTE: The order also specifies an expiry date A few additional order types that represent variations on the market and limit orders are as follows: Market-not-held order • This is a market order to be executed at the opening of the market Similarly a market on close order is a market order to be executed at market close Types of Trades Principal trades A principal trade is a trade with a broker in which the broker commits capital to facilitate the prompt execution of the trader’s order Such trades are used most when the order: • Is larger and/or • More urgent than can be accommodated within the normal flow of trading Portfolio trades –––––––––––––––––––––––––––––––––––––– Copyright © FinQuiz.com All rights reserved –––––––––––––––––––––––––––––––––––––– FinQuiz Notes Reading 35 Reading 35 Execution of Portfolio Decisions A portfolio trade involves an order to trade in a specific basket (list) of securities Portfolio trades are: • Relatively low cost because diversification (implied by multiple security issues) reduces the risk to the other side of the trade 2.2 Types of Markets 2.2.1) Quote-Driven (Dealer) Markets Quote-driven markets are markets in which trades are executed with a dealer—a business entity that is ready to take the other side of an order to buy or sell an asset at established firm prices • A dealer’s bid price is the price at which he/she will buy a security, and the ask price is the price at which he/she will sell a security The quantities associated with the bid and ask price are known as the bid size and ask size respectively • The inside bid or market bid is the highest and best bid The inside ask or market ask is the lowest or best ask The market bid and ask prices make up the inside quote or market quote and the difference between them is the inside or market bid-ask spread (inside ask less inside bid) The midquote is halfway between the market bid and ask prices • A closed-book market is a market in which the limit order book is not visible to the public, and traders rely on brokers to locate the best price • In a ‘pure’ dealer market, a dealer is a counterparty to every trade and public traders’ limit orders not compete with dealers’ bids and asks FinQuiz.com price improvement will result in an effective spread that is lower than the quoted spread o The effective spread is a better representation of the true cost of a transaction because it captures both price improvement and market impact NOTE: • The average effective spread is the mean effective spread of over all transactions in the stock in the period under study • Spreads are wider for riskier and less liquid securities Practice: Example Volume 6, Reading 35 2.2.2) Order-Driven Markets Order driven markets are markets in which trades take place between public investors, usually without intermediation by designated dealers Public limit orders establish transaction prices In order-driven markets: • There might be more competition for orders • A trade may be delayed, or may not be executed at all because a dealer is not present (execution uncertainty) • Traders cannot choose with whom they trade because a pre-specified set of rules governs the execution of orders Dealers’ Role Examples: Dealers can help in the following ways: Toronto Stock Exchange for equities, International Securities Exchange for options, and Hotspot FX for foreign exchange • Dealers help markets operate continuously by being ready to the opposite side of the trade (especially in markets that lack natural liquidity) • Dealers passively provide immediacy or bridge liquidity, the price of which is the bid-ask spread (they sometimes also take an active role in price setting to turn over inventory) • Dealers play an important role in markets requiring negotiation of the terms of the instrument, such as forward and swap markets Trade Costs The following are measures of trade costs: • The size of the quoted bid-ask spread as a proportion of the quote midpoint • The effective spread is the spread at which a trader actually transacts Sometimes a dealer steps in front of an order to improve on the prior best ask or bid price to take an incoming market order The Types of Order-Driven Markets Electronic Crossing Networks These are markets in which buy and sell orders are batched and crossed at a specific point in time Crossing networks mainly serve institutional investors Some benefits are as follows: • Both buyers and sellers avoid the costs of dealer services • Traders avoid the effects a large order can have on execution prices (market impact) • It prevents information leakage • Anonymity of traders is preserved • Commissions are paid but are typically low Some drawbacks are as follows: Reading 35 Execution of Portfolio Decisions • Participants cannot be guaranteed that their trades will find an opposing match (execution uncertainty) • Crossing networks provide no price discovery (the adjustment of prices to equilibrate supply and demand) Auction Markets These are markets in which the orders of multiple buyers compete for execution Auction markets can further be categorized into: • Periodic or batch auction markets (where trading occurs at a single price at a pre-specified point in time) An example is the reopening of the Tokyo Stock Exchange after the lunch break • Continuous auction markets (where trades are executed at any time during the day) In contrast to electronic crossing networks, auction markets: • Provide price discovery • Lessen the problem of partial fills Automated Auctions (Electronic Limit-Order Markets) These are computer-based auctions that operate continuously within the day using a specified set of rules to execute orders Electronic communications networks (ECNs), such as Paris Bourse in France, are an example of automated auctions for equities In contrast to crossing networks, ECNs: • Operate continuously • Provide price discovery Like crossing networks, ECNs: • Provide anonymity • Are computer-based 2.2.3) Brokered Markets Brokered markets are markets in which transactions take place through brokers, away from public markets The brokers collect commission for representation of the trade These markets are important: • In countries where public markets are small • Where it is difficult to find liquidity • For block transactions (a block order is large relative to the liquidity ordinarily available from dealers or other markets), in which a broker might occasionally position a portion of the block (act as a principal with capital at risk) NOTE: FinQuiz.com Many parties can and perform parts of dealer functions Hence market classifications are simplifications 2.2.4) Hybrid Markets Hybrid markets are combinations of the previously described market types An example is the NYSE, which offers elements of batch auction market, continuous auction markets and quote-driven markets 2.3 The Roles of Brokers and Dealers Brokers A broker is an agent of the investor In return for a commission, the broker provides services including the following: • Representing the order: The broker’s primary task is to represent the order to the market • Finding the opposite side of a trade: The broker locates the buyer or seller for the trade and may, in return for compensation, act as a dealer by buying and selling shares for his own account • Supplying market information: Market intelligence provided by the broker can be valuable, including information about the identity of traders and the strength of trading interest • Providing discretion and secrecy: Brokers help in preserving the anonymity of the traders’ trading intentions Such secrecy does not extend to the selected broker • Providing other supporting investment services: A broker may provide a range of other services including providing financing, record keeping, cash management, and safekeeping of securities (such services and more are provided in relationships known as prime brokerage) • Supporting the market mechanism: Brokerage commissions indirectly assure the continuance of the needed market facilities Dealers The relationship between the trader and a dealer is adversarial • A dealer gains from wider bid-ask spreads while the trader gains from narrower bid-ask spreads • Dealers want to know who is active in the market, how informed traders are, and how urgent their interest in transacting with the dealer is, in order to manage profits and adverse selection risk (the risk of trading with a more informed trader) The trader does not want the dealer to know these facts • Buy-side traders are often strongly influenced by sell-side traders such as dealers The buy-side trader should manage the relationships with dealers, remembering that his first allegiance is to his clients 2.4 Evaluating Market Quality Reading 35 Execution of Portfolio Decisions Markets quality can be judged by the degree to which it provides: • Liquidity • Transparency • Assurity of completion Liquidity A liquid market has the following characteristics: • The market has relatively low bid-ask spreads: Such a market is called ‘tight’ Quoted and effective spreads are low • The market is deep: Depth means that big trades tend not to cause large price movements Deep markets have high quoted depth (quantity available for trading) Costs of trading large amounts of an asset are relatively small • The market is resilient: Discrepancies between market price and intrinsic value tend to be small and corrected quickly Following factors contribute to making a market liquid: • Many buyers and sellers: This increases the chance of locating the opposite side of a trade at a competitive price • Diversity of opinion, information, and investment needs among market participants: If investors are alike, they will make similar trades Diversity in the factors described above increases the chance that a buyer of a security can find a seller In general, a large pool of investors enhances diversity • Convenience: A readily accessible physical location or a well thought out electronic platform attracts investors • Market Integrity: Ethical rules set by market operatives and effective regulation play a major role in increasing public confidence in the market’s integrity The advantages of liquidity include the following: • Traders can trade rapidly without a major impact on price • Information motivated traders can trade easily bringing their insights into security prices • Corporations can attract capital easily Investors will pay a premium for securities that possess liquidity Higher security prices will enhance corporate value and lower the cost of capital FinQuiz.com Transparency Transparency ensures that: • Individuals can quickly, easily and inexpensively obtain accurate information about quotes and trades pretrade transparency • Details on completed trades are quickly and accurately reported to the public—post-trade transparency Assurity of Completion Traders need to be sure that all parties to a trade will honor their commitments Assurity of completion depends on assurity of the contract (the parties to trades are held to fulfilling their obligations) Clearing entities that guarantee both sides of the trade can help ensure assurity of completion Practice: Example & 4, Volume 6, Reading 35 Reading 35 Execution of Portfolio Decisions THE COSTS OF TRADING 3.1 TRANSACTION COST COMPONENTS Trading costs have two major components: Explicit costs are direct costs of trading, such as broker commission costs, taxes, stamp duties, and fees paid to exchanges Implicit costs represent indirect trading costs They include the following: • The bid-ask spread • Market impact (or price impact) is the effect of the trade on transaction prices (for example, a large buy order may push the market ask price of a stock up, so that the remaining order is executed at a higher ask) • Missed trade opportunity costs arise from the failure to execute a trade in a timely manner If a trader places a limit order to buy a stock at a price of 99.00 but the ask is 99.04 the order will not execute Suppose the stock closes at 99.80 The difference (99.80-99.04= $0.76) reflects the missed trade opportunity cost This estimate could be quite sensitive to the time frame chosen for measurement • Delay costs (also called slippage) arise from the inability to complete the desired trade immediately due to its size and the liquidity of markets While a trade is delayed, information is leaked into the market Measurement of Costs Implicit costs are measured against some price benchmark • One benchmark is the time-of-trade midquote, which is used to calculate the effective spread • When precise information is lacking, the price benchmark is sometimes taken to be the volumeweighted average price (VWAP) • Opening and closing prices for a security are alternative benchmarks which use less information about prices and are less satisfactory (opening price is much easier to game) • The most exact approach to cost measurement is the implementation shortfall approach Volume-weighted average price The VWAP of a security is the average price at which the security traded during the day, where each trade price is weighted by the fraction of the day’s volume associated with the trade Examples: FinQuiz.com If a buy order for 500 shares was executed at $157.25 and the VWAP for the stock for the day was $156.00, the estimated implicit cost of the order would be 500($157.25-$156.00) = $625 • VWAP is less informative for trades that represent a large fraction of volume • VWAP can be gamed especially as the close of trading approaches and the VWAP estimate’s accuracy increases To address this, VWAP could be measured over multiple days Implementation Shortfall Approach Implementation shortfall is defined as the difference between the money return on a notional or paper portfolio in which positions are established at the prevailing price when the decision to trade is made (called the decision price, the arrival price, or the strike price) and the actual portfolio’s return It correctly captures all elements of transaction costs (both explicit and implicit) Implementation shortfall can be analyzed into four components: • Explicit costs: commissions, fees and taxes • Realized profit/loss: reflects the difference between the execution price and the relevant decision price (usually taken to be the previous day’s close) The calculation is based on the amount of order actually filled • Delay costs (slippage): reflects the change in price (close-to-close price movement) over the day an order is placed if the order is not executed that day The calculation is based on the amount of the order actually filled • Missed trade opportunity cost (unrealized profit/loss): reflects the price difference between the trade cancellation price and the original benchmark price based on the amount of the order that was not filled NOTE: Market movement is a component of the last three of these costs Practice: Illustration of the calculation of implementation shortfall, Volume 6, Reading 35 Reading 35 Execution of Portfolio Decisions NOTE: • The shortfall computation is simply reversed for selling—the return on the paper portfolio is subtracted from the return on the actual portfolio Disadvantages The application of the implementation shortfall approach is hampered when: • An asset trades infrequently because the decision price is then hard to determine • A market lacks transparency (accurate price and/or quote information) Adjustment for Market Movements Suppose the implementation cost is 87 bps and the market has risen by 100 bps over the period of trading If the beta of the security is 1, then the market model predicts that the return on the asset equals: Ri =αi + βiRM Hence, the predicted return will be 1(1%) = 1% (given that, with daily returns, α will be close to zero) The market-adjusted implementation shortfall would be 0.87%-1.0% = -0.13% NOTE: Some managers measure shortfall with respect to a portfolio in which component costs are at expected levels Comparison of VWAP and Implementation Shortfall Advantages Volume Weighted Average Price Implementation Shortfall • Easy to compute • Easy to understand • Can be computed quickly • Works best for comparing smaller trades in non-trending markets • Links trading to portfolio manager activity; can relate cost to the value of ideas • Recognizes the tradeoff between immediacy and price • Allows attribution of costs • Can be built into portfolio optimizers to reduce turnover and increase realized performance • Cannot be gamed FinQuiz.com Volume Weighted Average Price Implementation Shortfall • Does not account for costs of trades delayed or canceled • Becomes misleading when trade is a substantial proportion of trading volume • Not sensitive to these trade size or market conditions • Can be gamed by delaying trades • Requires extensive data collection and interpretation • Imposes an unfamiliar evaluation framework on traders Source: Exhibit Volume 6, Reading 35 3.2 Pre-trade Analysis: Econometric Models for Costs Econometric models can be used to build reliable pretrade estimates The theory of market microstructure suggests that trading costs are nonlinearly related to certain factors, including the following: • Stock liquidity characteristics (e.g market capitalization, price level, volume, trading frequency, bid-ask spread, index membership); • Risk (e.g the volatility of the stock’s returns); • Trade size relative to available liquidity (e.g order size divided by average daily volume); • Momentum (e.g it is more costly to buy in an up market than in a down market); • Trading style (e.g more aggressive styles are associated with higher costs) Regression analysis can be used to determine the relationships of the above factors with cost Uses The estimated cost function can be used: • To form a pre-trade estimate of the cost of trading which can then be compared to actual realized costs to assess execution quality • To help the portfolio manager determine the right trade size to order (for example if expected excess return is 5%, but round-trip transaction costs are also 5%, the excess return would be eroded The optimal trade size should be decreased) Reading 35 Execution of Portfolio Decisions FinQuiz.com Practice: Example Volume 6, Reading 35 TYPES OF TRADERS AND THEIR PREFERRED ORDER TYPES 4.1 SUMMARY The Types of Traders Traders can be classified by their motivation to trade, as follows: Information-motivated traders trade on information that has limited value if not quickly acted upon They: • often stress liquidity and speed of execution over securing a better price • are likely to use market orders (to hide their intentions) and rely on market makers • Often trade in large blocks Value-motivated traders act on value judgments based on research and trade only when the price moves into their value range Value traders: • Trade infrequently and are motivated only by price • Trade over lengthy trading horizons and are patient to secure a better price Liquidity motivated traders not transact to reap profit from an information advantage They transact to release cash proceeds, adjust market exposure, or fund cash needs, and tend to be counterparties to more knowledgeable traders Passive traders seek liquidity in their rebalancing transactions and are much more concerned with the cost of trading • They seek lower-cost execution • Their trades resemble dealers Some other trader types are as follows: • Dealers profit by earning bid-ask spreads and have short trading time horizons • Arbitrageurs are sensitive to both price and speed of execution • Day traders rapidly buy and sell stocks, and like dealers, often seek to profitably accommodate the trading demands of others Time versus Price Preference Trader Motivation Trading Time Horizon Informationmotivated New Information Minutes to hours Time Valuemotivated Perceived valuation errors Days to weeks Price Liquiditymotivated Invest cash or divest securities Minutes to hours Time Passive Rebalancing, investing/ divesting cash Days to weeks Price Dealers and Minutes to Accommodation day traders hours Passive, indifferent Source: Exhibit Volume 6, Reading 35 4.2 Traders’ Selection of Order Types 4.2.1) Information-Motivated Traders Information traders believe that they need to trade immediately and often trade large quantities in specific names These traders: • may use fast action principal trades • use less obvious orders, such as market orders, to disguise their trading intentions in order to prevent their information edge from diminishing 4.2.2) Value-Motivated Traders The value motivated trader develops an estimate of value and waits for market prices to fall in the range of that estimate These traders: • use limit orders, because price is more important • Sometimes operate as ‘the dealer’s dealer’, buying stock when dealers want to sell 4.2.3) Liquidity-Motivated Traders NOTE: This classification of traders is relevant to both equity and fixed-income markets The commitment or release of cash is the primary objective These traders: • Use market, market-not-held, best efforts, participate, principal traders, portfolio trades, and orders on ECNs and crossing networks Reading 35 Execution of Portfolio Decisions • Desire low commissions and small impact, and can tolerate some execution uncertainty FinQuiz.com • Face execution uncertainty • Use orders that are best suited to trading that is neither large nor heavily concentrated 4.2.4) Passive Traders Low-cost trading is the mains objective These traders: • Use limit orders, portfolio trades, and crossing networks • Favor low commissions, low impact, and reduction of bid-ask spreads 5.1 TRADE EXECUTION DECISIONS AND TACTICS Decisions Related to the Handling of a Trade Considerations include the following: • Small, liquidity-oriented trades can be executed via direct market access (DMA) and algorithmic trading • Large, information-laden trades can be executed using the skills of senior traders • The trader must be aware of client trading restrictions, cash balances, and brokerage allocations, if any 5.2 Objectives in Trading and Trading Tactics Following are various types of trading techniques: 5.2.1) Liquidity-at-Any-Cost Trading Focus This technique is used by information traders who trade in large block sizes and demand immediacy Traders with such a focus: • Usually attract brokers demanding a high commission rate • Usually recognize that the methods they use are expensive but pay the price for timely execution NOTE: Sometimes, urgency will place a normally nonaggressive trader into this category This technique is used to execute large orders, particularly in thinly traded issues • Traders with such a focus use brokers to skillfully work such orders by placing a best efforts, marketnot-held, or participate order • Such a focus is less useful for informationmotivated traders • Trader loses control of the trade and does not know whether the broker would act in his/her best interests 5.2.4) Advertise-to-Draw-Liquidity Trading Focus This technique is used for IPOs, secondary offerings and sunshine traders If publicity attracts enough traders, there may be little or no market impact Such orders bear the risk of trading in front of the order 5.2.5) Low-Cost-Whatever-the-Liquidity Trading Focus Limit orders are the chief example of this type of order This type of order: • Is best suited for passive and value-motivated investors • Has the advantages of low commissions, low impact and possible elimination of dealer spread • Could cause traders to end up ‘chasing the market’ • Has execution uncertainty, and if the limit price becomes stale, the order may be executed at an unrevised, undesirable price 5.2.6) Trading Technique Summary 5.2.2 Costs-Are-Not-Important Trading Focus Traders with such a focus use market orders (and its variations) since they trust the market to generate a fair price They pay ordinary spreads and commissions for speed of execution Market orders: • Work best for smaller trades and more liquid stocks • Are inexpensive for a broker to execute • Cause traders to lose control over the trade 5.2.3) Need-Trustworthy-Agent Trading Focus Source: Exhibit Volume 6, Reading 35 5.3 Automated Trading • Algorithmic trading refers to electronic trading subject to quantitative rules and user-specified benchmarks and constraints • Related, but distinct, trading strategies include using portfolio trades and smart routing (use of algorithms to route an order to the most liquid venue) Reading 35 Execution of Portfolio Decisions 5.3.1) The Algorithmic Revolution The underlying logic behind algorithmic trading is to break large orders into smaller orders that blend into the normal trading volume in order to moderate price impact • Automated trading requires constant monitoring to avoid taking unintentional risk (e.g an unbalanced portfolio) NOTE: FinQuiz.com These strategies solve for the optimal trading strategy that minimizes trading costs as measured by the implementation shortfall method Opportunistic Participation Strategies These strategies also involve trading over time: passive trading combined with the opportunistic seizing of liquidity This liquidity strategy is not a true participation strategy Examples include pegging and discretion strategies (that use reserve or hidden orders and crossing) Specialized Strategies • Today’s traders have become strategists and tacticians, whereas in the past, their primary task was managing broker relationships • The meat-grinder effect states that in order for a large equity order to get done, it must often be broken up into smaller orders 5.3.2) Classification of Algorithmic Execution Systems Logical Participation Strategies • Simple Logical Participation Strategies • Implementation Shortfall Strategies Opportunistic Strategies Specialized Strategies Simple Logical Participation Strategies This is the most common class of algorithms in use Following are its types: • Volume-weighted average price (VWAP) strategy breaks up an order over time to match or improve upon the VWAP for the day It can either use historical volume data or forward-looking volume predictors • Time-weighted average price (TWAP) strategy breaks up the order in proportion to time to match or beat a time weighted or equal weighted average price The strategy is useful in thinly traded assets whose volume patterns might be erratic and can be reactive or proactive • Percentage-of-volume strategy is a strategy in which trading takes place in proportion to overall market volume until the order is completed These include passive order strategies, hunter strategies (that seek liquidity), market-on-close algorithms, smart routing, and other specialized strategies 5.3.3) The Reasoning behind Logical Participation Algorithmic Strategies • Simple logical participation strategies are based on the premise that breaking up the order into smaller sub-blocks yields a lower average market or price impact • Implementation shortfall strategies believe in minimizing a weighted average of market impact costs and missed trade opportunity costs Since the volatility of trade value or trade cost increases with trading horizon, these strategies are typically front-loaded (trade heavily early in the trading day) The implementation shortfall algorithm solves for an objective function that minimizes expected total cost and variance of possible cost outcomes This is consistent with the portfolio optimization problem Important: Generally: • Orders that are small relative to average daily volume, have low urgency and low spreads are ideal for VWAP algorithms • Orders that are small but have high urgencies are ideal for implementation shortfall algorithms • Orders that are large should be traded using a broker or crossing system to mitigate large spreads Practice: Example under Exhibit 12 Volume 6, Reading 35 Implementation Shortfall Strategies 6.1 SERVING THE CLIENT’S INTERESTS CFA Institute Trade Management Guidelines The Guidelines define best execution as: • “the trading process Firms apply that seeks to maximize the value of a client’s portfolio within the client’s stated investment objectives and constraints” Reading 35 Execution of Portfolio Decisions The definition identifies four characteristics: • Best execution cannot be evaluated independently • Best execution is a prospective, statistical, and qualitative concept that cannot be known with certainty ex ante • Best execution can be measured on an ex post basis, even though such measurement on a tradeby-trade basis may not be meaningful in isolation • Best execution is a process, not an outcome that is interwoven into repetitive and continuing relationships 6.2 Disclosures: Firms should disclose to clients and prospects: • General information regarding trading techniques, venues and agents • Actual or potential trading related conflicts of interest Recordkeeping: Firms should maintain documentation that supports: • Compliance with the firm’s policies and procedures • Disclosures provided to clients NOTE: The records may also support a firm’s broker selection practices NOTE: These guidelines are a compilation of recommended practices and not standards The Importance of an Ethical Focus The code of both buy-side and sell-side traders is that verbal agreements will be honored Over time, the disappearance of commissions has caused costs to become implicit and markets to become more adversarial However, in every case, the ethical focus of the portfolio manager and the buy-side trader must be the interests of the client and all actions should be consistent with the trader’s fiduciary responsibilities Practice: End of Chapter Practice Problems for Reading 35 & FinQuiz Item-set ID# 13345 The Trade Management Guidelines are divided into three areas: Processes: Firms should establish formal policies and procedures that have the goal of maximizing asset value of client portfolios through best execution and that provide guidance to measure and manage the quality of trade decisions FinQuiz.com ... ensure assurity of completion Practice: Example & 4, Volume 6, Reading 35 Reading 35 Execution of Portfolio Decisions THE COSTS OF TRADING 3. 1 TRANSACTION COST COMPONENTS Trading costs have two major... eroded The optimal trade size should be decreased) Reading 35 Execution of Portfolio Decisions FinQuiz. com Practice: Example Volume 6, Reading 35 TYPES OF TRADERS AND THEIR PREFERRED ORDER TYPES... costs Practice: Illustration of the calculation of implementation shortfall, Volume 6, Reading 35 Reading 35 Execution of Portfolio Decisions NOTE: • The shortfall computation is simply reversed