Trading Systems: What Is A Trading System?

A trading system is a group of specific parameters that combine to create buy and sell signals for a given security. Trading systems can be developed using many different technologies, including Microsoft Excel, MATLAB®, TradeStation, R, Python, and other platforms and languages. The buy and sell signals from these platforms may appear in a file for you to execute or be programmatically executed using a brokerage that supports automated trading.

There are countless different inputs that can be used when building trading systems. Technical indicators are the most common, but many trading systems incorporate fundamental data, such as revenue, cash flow, debt-to-equity, or other financial ratios. Others even incorporate news, tweets, and other data from around the web that could provide a signal. The only requirement is that the data must be represented in a way that a computer can analyze.

Technical indicators

In basic trading systems, two or more technical indicators are combined to create buy and sell trading signal. For example, a moving average crossover trading system uses two moving averages as parameters, the long-term and the short-term, to create trading signals. A buy signal is generated when the short-term crosses above the long-term and a sell signal is generated when the short-term crosses below the long-term.

In advanced trading systems, machine learning or artificial intelligence techniques may be used to fine-tune the settings for these parameters (e.g. the number of days used in a moving average calculation) or identify relationships between security prices and/or external factors. These techniques can become very complex - as is the case with hedge funds like Renaissance Technologies LLC that employ teams of mathematicians with PhDs.

Traders spend a lot of time optimizing trading systems, by changing the values of each parameter, to reduce risk and increase returns. For example, longer-term moving averages in the moving average crossover trading system may lead to delayed signals, so traders may experiment with using shorter-term moving averages. Traders may also explore adding new parameters into the mix to reduce risk or increase returns.

Advantages of Trading Systems

• Removes cognitive biases. Cognitive biases take a large toll on trading income and trading systems remove most of them from the equation. Traders who are unable to cope with losses second-guess their decisions, while those that recently lost money may miss out on new opportunities. Trading systems remove traders from actual buy and sell decision-making and create more predictable results.
• Saves time. Trading systems that are developed and optimized may require less effort to maintain than sitting by a screen all day finding opportunities and placing trades. Traders can also develop trading systems any time of the day, which means that they can spend market hours away from the screen.
• You can outsource some of the work. Many software developers specialize in developing trading systems. If you come up with the rules, they can implement and backtest the trading systems to see how they perform. Some companies also sell off-the-shelf trading systems, but it's generally a good idea to exercise caution when considering them.

Disadvantages of Trading Systems

• Requires unique skillsets. Developing trading systems on your own requires a solid understanding of both technical analysis and software development. While you can outsource software development, you will still need the ability to effectively translate your innate knowledge of technical analysis into specific rules that can be implemented by a computer algorithm rather than relying on intuition.
• Can be difficult to optimize. Trading systems must include many different assumptions, such as slippage, transaction costs, and changing market dynamics. Even when accounting for these factors, it's impossible to test trading systems before pushing them live, which means that there's a degree of uncertainty involved. Problems may arise in live trading that can be costly and difficult to fix.
• Requires a large initial investment. Trading systems take a lot of time to initially develop and test before pushing them live. During this time, you will not be generating any trading revenue, which could be costly for some traders. Trading systems also require ongoing maintenance to fine-tune parameters and address any changes in the market.

Do They Really Work?

There is no shortage of scammers promising trading systems in exchange for hundreds or thousands of dollars. But, there's also no question that there have been many successful trading systems in the past and there will be many more in the future.

The most famous example of a successful trading system was the one developed and implemented by Richard Dennis and Bill Eckhardt - the Original Turtle Traders. In 1983, the two had a dispute over whether a good trader was born or made. So, they took some people off the street and trained them based on their now-famous Turtle Trading Systems. They gathered 13 traders and ended up making 80 percent annually over the following four years.

It's easy to identify most scams by adhering to the age old "if it's too good to be true, then it probably is" idiom. For example, a guarantee of 2,500 percent returns per year is clearly outrageous as it promises that with only $5,000, you could make $125,000 in a single year. After five years, that amount would be nearly $50 billion. If this were true, the creators could have traded their way into becoming a billionaire in short order!

If you have an intuition when it comes to the market, and you can translate that intuition into trading rules, then you can build a trading system. Likewise, if you have expertise in emerging areas like machine learning and artificial intelligence, and access to ample liquidity and execution speeds, you can build a trading system. Trading systems aren't easy to develop, and they require a deep understanding of the markets, but they can be very profitable.

Coming Up

In the next section, we will look at how to design your own trading system.