Automated Trading Systems: The Pros and Cons.
Jean Folger has 15+ years of experience as a financial writer covering real estate, investing, active trading, the economy, and retirement planning. She is the co-founder of PowerZone Trading, a company that has provided programming, consulting, and strategy development services to active traders and investors since 2004.
Updated March 04, 2021.
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Reviewed by Somer Anderson.
Somer G. Anderson is CPA, doctor of accounting, and an accounting and finance professor who has been working in the accounting and finance industries for more than 20 years. Her expertise covers a wide range of accounting, corporate finance, taxes, lending, and personal finance areas.
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Fact checked by Amanda Bellucco-Chatham.
Amanda Bellucco-Chatham is an editor, writer, and fact-checker with years of experience researching personal finance topics. Specialties include general financial planning, career development, lending, retirement, tax preparation, and credit.
What Is an Automated Trading System?
Automated trading systems — also referred to as mechanical trading systems, algorithmic trading, automated trading or system trading — allow traders to establish specific rules for both trade entries and exits that, once programmed, can be automatically executed via a computer. In fact, various platforms report 70% to 80% or more of shares traded on U.S. stock exchanges come from automatic trading systems.
Traders and investors can turn precise entry, exit, and money management rules into automated trading systems that allow computers to execute and monitor the trades. One of the biggest attractions of strategy automation is that it can take some of the emotion out of trading since trades are automatically placed once certain criteria are met.
The trade entry and exit rules can be based on simple conditions such as a moving average crossover or they can be complicated strategies that require a comprehensive understanding of the programming language specific to the user’s trading platform. They can also be based on the expertise of a qualified programmer.
Automated trading systems typically require the use of software linked to a direct access broker, and any specific rules must be written in that platform’s proprietary language. The TradeStation platform, for example, uses the EasyLanguage programming language. On the other hand, the NinjaTrader platform utilizes NinjaScript. The figure below shows an example of an automated strategy that triggered three trades during a trading session.
A five-minute chart of the ES contract with an automated strategy applied.
Establishing Trading “Rules”
Some trading platforms have strategy-building “wizards” that allow users to make selections from a list of commonly available technical indicators to build a set of rules that can then be automatically traded. The user could establish, for example, that a long position trade will be entered once the 50-day moving average crosses above the 200-day moving average on a five-minute chart of a particular trading instrument. Users can also input the type of order (market or limit, for instance) and when the trade will be triggered (for example, at the close of the bar or open of the next bar), or use the platform’s default inputs.
Many traders, however, choose to program their own custom indicators and strategies. They will often work closely with the programmer to develop the system. While this typically requires more effort than using the platform’s wizard, it allows a much greater degree of flexibility, and the results can be more rewarding. Just like anything else in the trading world, there is, unfortunately, no perfect investment strategy that will guarantee success.
Once the rules have been established, the computer can monitor the markets to find buy or sell opportunities based on the trading strategy’s specifications. Depending on the specific rules, as soon as a trade is entered, any orders for protective stop losses, trailing stops and profit targets will be automatically generated. In fast-moving markets, this instantaneous order entry can mean the difference between a small loss and a catastrophic loss in the event the trade moves against the trader.
Advantages of Automated Systems.
There is a long list of advantages to having a computer monitor the markets for trading opportunities and execute the trades, including:
Minimizing Emotions.
Automated trading systems minimize emotions throughout the trading process. By keeping emotions in check, traders typically have an easier time sticking to the plan. Since trade orders are executed automatically once the trade rules have been met, traders will not be able to hesitate or question the trade. In addition to helping traders who are afraid to “pull the trigger,” automated trading can curb those who are apt to overtrade — buying and selling at every perceived opportunity.
Backtesting.
Backtesting applies trading rules to historical market data to determine the viability of the idea. When designing a system for automated trading, all rules need to be absolute, with no room for interpretation. The computer cannot make guesses and it has to be told exactly what to do. Traders can take these precise sets of rules and test them on historical data before risking money in live trading. Careful backtesting allows traders to evaluate and fine-tune a trading idea, and to determine the system’s expectancy – i.e., the average amount a trader can expect to win (or lose) per unit of risk.
Preserving Discipline.
Because trade rules are established and trade execution is performed automatically, discipline is preserved even in volatile markets. Discipline is often lost due to emotional factors such as fear of taking a loss, or the desire to eke out a little more profit from a trade. Automated trading helps ensure discipline is maintained because the trading plan will be followed exactly. In addition, “pilot error” is minimized. For instance, if an order to buy 100 shares will not be incorrectly entered as an order to sell 1,000 shares.
One of the biggest challenges in trading is to plan the trade and trade the plan . Even if a trading plan has the potential to be profitable, traders who ignore the rules are altering any expectancy the system would have had. There is no such thing as a trading plan that wins 100% of the time. After all, losses are a part of the game. But losses can be psychologically traumatizing, so a trader who has two or three losing trades in a row might decide to skip the next trade. If this next trade would have been a winner, the trader has already destroyed any expectancy the system had. Automated trading systems allow traders to achieve consistency by trading the plan.
Improving Order Entry Speed.
Since computers respond immediately to changing market conditions, automated systems are able to generate orders as soon as trade criteria are met. Getting in or out of a trade a few seconds earlier can make a big difference in the trade’s outcome. As soon as a position is entered, all other orders are automatically generated, including protective stop losses and profit targets. Markets can move quickly, and it is demoralizing to have a trade reach the profit target or blow past a stop-loss level – before the orders can even be entered. An automated trading system prevents this from happening.
Diversifying Trading.
Automated trading systems permit the user to trade multiple accounts or various strategies at one time. This has the potential to spread risk over various instruments while creating a hedge against losing positions. What would be incredibly challenging for a human to accomplish is efficiently executed by a computer in milliseconds. The computer is able to scan for trading opportunities across a range of markets, generate orders and monitor trades.
Minimize emotional trading Allows for backtesting Preserves the trader’s discipline Allows multiple accounts.
Mechanical failures can happen Requires the monitoring of functionality Can perform poorly.
Automated Trading Systems: The Pros and Cons
