
Algo trading is a type of trading that uses computer programs to automatically execute trades based on predefined rules and algorithms.
These programs can analyze vast amounts of data in real-time, making it possible to react faster than human traders.
The goal of algo trading is to make consistent profits by minimizing emotional decision-making and maximizing efficiency.
By using algorithms, traders can also backtest and optimize their strategies, reducing the risk of losses.
Types of Algo Trading
Algo trading is a broad term that encompasses various strategies and approaches.
Market Making is a type of algo trading that involves providing liquidity to the market by buying and selling securities at prevailing market prices.
High-Frequency Trading is a strategy that uses complex algorithms to execute trades at extremely high speeds, often in fractions of a second.
What Are Algorithms?
Algorithms are a set of instructions that are introduced to carry out a specific task, such as trading.

These instructions are designed to automate trading and generate profits at a frequency impossible to a human trader.
Algorithmic trading rules out the human (emotional) impact on trading activities, making it a reliable option for institutional investors like investment banks, pension funds, and hedge funds.
The use of sophisticated algorithms is common among these institutions due to the large volumes of shares they trade daily, allowing them to get the best possible price at minimal costs without significantly affecting the stock price.
Algorithms can be used to set rules based on pricing, quantity, timing, and other mathematical models, making them a valuable tool for traders who want to automate their trading activities.
Algorithmic trading can be executed through platforms like ProRealTime and MetaTrader 4 (MT4), as well as through native APIs, making it easy to implement and use.
Trend-Following
Trend-Following is a common algorithmic trading strategy that follows trends in moving averages, channel breakouts, price level movements, and related technical indicators.

These strategies are easy to implement through algorithmic trading because they don't require making predictions or price forecasts. Trades are initiated based on the occurrence of desirable trends.
Using 50- and 200-day moving averages is a popular trend-following strategy. This involves monitoring the relationship between these two moving averages to determine trading opportunities.
Trend-following strategies are straightforward to implement through algorithms, making them a great starting point for beginners.
Mean Reversion
Mean reversion is a mathematical methodology used for stock investing, where a stock's price tends to revert to its average price over time.
The idea is that both a stock's high and low prices are temporary, and that a stock's price tends to have an average price over time.
To apply mean reversion, you first need to identify the trading range for a stock, and then compute the average price using analytical techniques as it relates to assets, earnings, etc.
The standard deviation of the most recent prices, such as the last 20, is often used as a buy or sell indicator.

Stock reporting services like Yahoo! Finance and Morningstar commonly offer moving averages for periods such as 50 and 100 days, but you still need to identify the high and low prices for the study period.
If the current market price is less than the average price, the stock is considered attractive for purchase, with the expectation that the price will rise.
On the other hand, if the current market price is above the average price, the market price is expected to fall, reverting to the average.
Mean reversion involves computing the average price of a stock's temporary high and low prices, and using it to make trading decisions.
The Ornstein-Uhlenbeck stochastic equation is an example of a mean-reverting process that can be applied to stock investing.
Scalping
Scalping is a type of liquidity provision where traders try to earn the bid-ask spread by quickly establishing and liquidating positions, usually within minutes or less.
This procedure is only profitable as long as price movements are less than the spread.

A market maker is essentially a specialized scalper who trades in large volumes using sophisticated systems and technology.
Market makers are bound by exchange rules, such as NASDAQ's requirement for each market maker to post at least one bid and one ask at some price level to maintain a two-sided market.
Advantages and Disadvantages
Algo trading offers several advantages, including best execution, low latency, and reduced transaction costs. This means that trades are executed quickly and accurately, often at the best possible prices.
One of the key benefits of algo trading is its ability to execute trades instantly, with a high chance of execution at the desired levels. This reduces the risk of significant price changes and ensures that trades are timed correctly.
Some of the advantages of algo trading include:
- Best Execution: Trades are often executed at the best possible prices.
- Low Latency: Trade order placement is instant and accurate.
- Reduced transaction costs.
- No Human Error: Reduced risk of manual errors or mistakes when placing trades.
- Backtesting: Algo-trading can be backtested using available historical and real-time data.
However, algo trading also has some disadvantages, including latency, black swan events, and dependence on technology. These can result in missed opportunities or losses, and highlight the importance of robust systems and contingency planning.
Advantages

Algorithmic trading offers several advantages that make it an attractive option for traders.
One of the main benefits is Best Execution, which ensures that trades are executed at the best possible prices.
Algo-trading provides instant and accurate trade order placement, resulting in Low Latency. Trades are timed correctly and instantly to avoid significant price changes.
Reduced transaction costs are another advantage of algo-trading. This is due to the elimination of manual errors or mistakes when placing trades.
Algo-trading also allows for simultaneous automated checks on multiple market conditions. This helps traders stay on top of market trends and make informed decisions.
No Human Error is a significant advantage of algo-trading, as it eliminates the risk of manual errors or mistakes when placing trades. This also negates the human tendency to be swayed by emotional and psychological factors.
The ability to Backtest algo-trading strategies using historical and real-time data is another benefit. This allows traders to see if a strategy is viable before implementing it.
Disadvantages

Algorithmic trading, while having its advantages, also comes with some significant disadvantages. Latency, or the delay in trade execution, can result in missed opportunities or losses.
Algorithmic trading relies on historical data and mathematical models to predict future market movements, but it's not immune to unforeseen market disruptions, known as black swan events, which can occur and result in losses.
Technical issues or failures can disrupt the trading process and result in losses. This is because algorithmic trading relies heavily on technology, including computer programs and high-speed internet connections.
Large algorithmic trades can have a significant impact on market prices, leading to losses for traders who are not able to adjust their trades in response. This can also increase market volatility at times, even leading to so-called flash crashes.
Algorithmic trading is subject to various regulatory requirements and oversight, which can be complex and time-consuming to comply with. This can lead to additional costs and administrative burdens for traders.

The development and implementation of algorithmic trading systems can be costly, and traders may need to pay ongoing fees for software and data feeds. This can be a significant expense for traders who are just starting out.
Algorithmic trading systems are based on predefined rules and instructions, which can limit the ability of traders to customize their trades to meet their specific needs or preferences. This lack of flexibility can be a disadvantage for traders who prefer a more intuitive or instinctive approach to trading.
Algorithmic trading relies on mathematical models and historical data, which means that it does not take into account the subjective and qualitative factors that can influence market movements. This lack of human judgment can be a disadvantage for traders who prefer a more human-centered approach to trading.
Here are some of the key disadvantages of algorithmic trading:
- Latency: delay in trade execution can result in missed opportunities or losses
- Black Swan Events: unforeseen market disruptions can occur and result in losses
- Technical Issues: technical failures can disrupt the trading process and result in losses
- Market Impact: large algorithmic trades can have a significant impact on market prices
- Regulatory Compliance: algorithmic trading is subject to various regulatory requirements and oversight
- High Capital Costs: development and implementation of algorithmic trading systems can be costly
- Limited Customization: algorithmic trading systems are based on predefined rules and instructions
- Lack of Human Judgment: algorithmic trading relies on mathematical models and historical data
Implementation and Strategy
Most algorithmic trading strategies are implemented using modern programming languages.

Some firms still use spreadsheets to design strategies, but this is becoming less common.
Orders can be transmitted from traders' systems via the FIX Protocol, which is a widely used standard in the industry.
Basic models can rely on as simple as a linear regression, while more complex models can use game-theoretic and pattern recognition techniques.
More complex methods, such as Markov chain Monte Carlo, have been used to create these models.
Strategy Implementation
Strategy implementation is a crucial step in creating a trading algorithm. Most of the algorithmic strategies are implemented using modern programming languages.
Some traders still implement strategies designed in spreadsheets, but this is becoming less common. Increasingly, large brokerages and asset managers are writing their algorithms to the FIX Protocol's Algorithmic Trading Definition Language (FIXatdl).
This allows them to specify exactly how their electronic orders should be expressed. Orders built using FIXatdl can then be transmitted from traders' systems via the FIX Protocol.
Basic models can rely on as little as a linear regression, while more complex game-theoretic and pattern recognition or predictive models can also be used to initiate trading. More complex methods such as Markov chain Monte Carlo have been used to create these models.
Here are some examples of simple trading algorithms:
- Short 20 lots of GBP/USD if the GBP/USD rises above 1.2012. For every 5 pip rise in GBP/USD, cover the short by 2 lots. For every 5 pip fall in GBP/USD, increase the short position by 1 lot.
- Buy 100,000 shares of Apple (AAPL) if the price falls below 200. For every 0.1% increase in price beyond 200, buy 1,000 shares. For every 0.1% decrease in price below 200, sell 1,000 shares.
Moving Average Example
A 20-day moving average trading algorithm is a popular and easy-to-implement strategy.
The algorithm buys a security if its current market price is below its average market price over some period.
This algorithm can be applied to various stocks, including Apple (AAPL).
The algorithm buys Apple shares if the current market price is less than the 20-day moving average.
The green arrow indicates a point in time when the algorithm would’ve bought shares.
The algorithm sells Apple shares if the current market price is more than the 20-day moving average.
The red arrow indicates a point in time when this algorithm would’ve sold shares.
Trading and Execution

Trading algorithms can execute trades at incredible speeds, accessing more than 17,000 global markets with reliable execution.
A large trade can potentially change the market price, known as a distortionary trade. This can be minimized by breaking up the trade into smaller batches, but this strategy comes with significant transaction costs and time-consuming execution.
To avoid market impact, traders can use a trading algorithm to instantly check the market price after each purchase. This can significantly reduce the number of transactions needed to complete the trade and the time taken to complete it.
For example, an investor wanting to buy one million shares in Apple might buy the shares in batches of 1,000 shares, taking over 83 hours to complete the trade. A trading algorithm can solve this problem by instantly checking the market price after each purchase.
Market and Timing
Algo-trading can be used across various time scales, from high-frequency trading (HFT) that executes orders at rapid speeds to mid- to long-term investments.
Algo-trading benefits different types of traders, including mid- to long-term investors, short-term traders, and systematic traders. These traders use automated trade execution to achieve their goals.
Systematic traders, in particular, find algo-trading efficient for trading rules and execution.
Market Timing

Market timing strategies are designed to generate alpha, and they use a methodology that includes backtesting, forward testing, and live testing. Backtesting is the first stage of market timing, and it involves simulating hypothetical trades through an in-sample data period.
To ensure accurate results, backtesting typically includes optimization to determine the most optimal inputs. This process can be refined by modifying the inputs +/- 10%, shmoosing the inputs in large steps, running Monte Carlo simulations, and accounting for slippage and commission.
Forward testing is the next stage, and it involves running the algorithm through an out-of-sample data set to ensure the algorithm performs within backtested expectations. This stage helps to validate the results of the backtesting process.
Live testing is the final stage of development, where the developer compares actual live trades with both the backtested and forward-tested models. Metrics compared include percent profitable, profit factor, maximum drawdown, and average gain per trade.
High-Frequency

High-frequency trading (HFT) firms represent 2% of the approximately 20,000 firms operating today, but account for 73% of all equity trading volume in the U.S.
These firms are masters of speed, using highly sophisticated algorithms to execute trades at lightning-fast speeds. In fact, HFT firms can process volumes of information simultaneously, something ordinary human traders cannot do.
HFT is a form of algorithmic trading characterized by high turnover and high order-to-trade ratios. It's been a subject of intense public focus since the 2010 Flash Crash, when algorithmic trading and HFT were cited as contributing factors to market volatility.
There are four key categories of HFT strategies: market-making based on order flow, market-making based on tick data information, event arbitrage, and statistical arbitrage. All portfolio-allocation decisions are made by computerized quantitative models.
Some of the major U.S. high frequency trading firms include Chicago Trading Company, Optiver, Virtu Financial, DRW, Jump Trading, Two Sigma Securities, GTS, IMC Financial, and Citadel LLC.
Market Making

Market making involves placing a limit order to sell above the current market price or a buy limit order below the current price on a regular and continuous basis to capture the bid-ask spread.
Market makers like Automated Trading Desk, which was bought by Citigroup in July 2007, account for a significant portion of trading volume. Automated Trading Desk alone accounted for about 6% of total volume on both NASDAQ and the New York Stock Exchange.
Tools and Platforms
Algo trading requires the right tools and platforms to execute your strategies efficiently. ProRealTime is a popular choice among traders, offering a range of features to support their goals.
To decide on the best platform for you, consider what you want to achieve – many traders use a combination of tools to accomplish multiple objectives. For example, some use MetaTrader 4 for its robust technical analysis capabilities.
If you're looking for a more customized solution, Native APIs might be the way to go, allowing you to create a tailored platform that meets your specific needs.
Choosing the Right Platform

Choosing the right platform for algorithmic trading can be overwhelming, but it's essential to consider your needs and goals.
You'll need computer programming knowledge to program the required trading strategy, or you can hire programmers or use premade trading software.
To place orders, you'll need network connectivity and access to trading platforms.
Access to market data feeds is also crucial, as the algorithm will need to monitor these for opportunities to place orders.
Backtesting is a critical step, and you'll need available historical data for this process, depending on the complexity of rules implemented in the algorithm.
Here are some popular algorithmic trading platforms to consider:
- ProRealTime
- MetaTrader 4
- Native APIs
System Architecture
A traditional trading system has three main parts: the exchange, the server, and the application. The exchange provides market data, including the latest order book, traded volumes, and last traded price (LTP) of a scrip.
The server receives this data and also acts as a store for a historical database. The data is analyzed at the application side, where trading strategies are fed from the user and can be viewed on the GUI.

The application is where trading strategies are fed from the user and can be viewed on the GUI. Once an order is generated, it is sent to the order management system (OMS), which transmits it to the exchange.
Old-school, high latency architecture is being replaced by newer, state-of-the-art, high infrastructure, low-latency networks. The complex event processing engine (CEP) is used for order routing and risk management.
The FIX protocol has made it easier to connect to different destinations, reducing the go-to market time for connecting with a new destination. Integration of third-party vendors for data feeds is no longer cumbersome.
Here are the three main parts of an algorithmic trading system:
- Exchange
- Server
- Application
In the U.S., spending on computers and software in the financial industry increased to $26.4 billion in 2005.
Case Studies and Examples
Algo trading has been a game-changer in the financial world. In 2008, the 300 securities firms and hedge funds that specialized in high-frequency trading took in profits of up to $21 billion.

A notable example of algo trading in action is Royal Dutch Shell, which is listed on both the Amsterdam Stock Exchange and the London Stock Exchange. The exchange rates and time differences between the two exchanges create a perfect opportunity for algo trading.
Studies have shown that a third of all European Union and United States stock trades in 2006 were driven by automatic programs, or algorithms. By 2009, high-frequency trading firms accounted for 60-73% of all US equity trading volume.
Here are some key statistics on the growth of algo trading:
- 2006: 40% of all orders on the London Stock Exchange were entered by algorithmic traders.
- 2007: 60% of all orders on the London Stock Exchange were predicted to be entered by algorithmic traders.
- 2010: An algorithmic trade entered by a mutual fund company triggered a wave of selling that led to the Flash Crash.
- 2016: About 80% of orders in foreign exchange markets were made via trading algorithms.
Case Studies
Algorithmic trading is not just a concept, it's a reality that's been playing out in markets around the world. A study by the TABB Group found that the US equities HFT industry was profitable to the tune of $1.3 billion in 2014, a significant decrease from the $21 billion peak in 2008.
Virtu Financial, a high-frequency trading firm, reported that they were profitable on an astonishing 1,277 out of 1,278 trading days over a five-year period. This demonstrates the benefits of trading millions of times every trading day.

By 2009, studies suggested that HFT firms accounted for 60-73% of all US equity trading volume. This number fell to around 50% in 2012.
In contrast, European markets had a higher proportion of algorithmic trades, with estimates ranging as high as 80% in some markets in 2008.
Algorithmic trading has also been on the rise in foreign exchange markets, with about 80% of orders being executed by algorithms in 2016, up from 25% in 2006.
Here's a breakdown of the estimated proportion of algorithmic trades in various markets:
These numbers demonstrate the significant impact that algorithmic trading has had on the financial markets. However, they also highlight the challenges and risks associated with this type of trading.
Examples of Simple
Simple trading algorithms can be surprisingly effective. They're often straightforward to implement and require minimal technical expertise.
In Example 1, we see a short-term trading strategy that involves shorting 20 lots of GBP/USD if it rises above 1.2012. This is a clear example of a simple algorithm that can be executed with ease.

For every 5 pip rise in GBP/USD, the algorithm covers the short by 2 lots, and for every 5 pip fall, it increases the short position by 1 lot. This shows how the algorithm adapts to changing market conditions.
Another example is buying 100,000 shares of Apple (AAPL) if the price falls below 200. This algorithm is designed to take advantage of a potential price drop.
For every 0.1% increase in price beyond 200, the algorithm buys 1,000 shares, and for every 0.1% decrease in price below 200, it sells 1,000 shares. This is a simple yet effective way to adjust to market fluctuations.
The 20-day moving average trading algorithm is another example of a simple yet effective strategy. It buys shares if the current market price is below the 20-day moving average and sells shares if the current market price is above it.
Here are some key characteristics of simple trading algorithms:
These examples demonstrate the power of simple trading algorithms in navigating the markets.
Concerns and Issues

Algorithmic trading has its fair share of concerns and issues. One major concern is the "black box-ness" of these systems, making it difficult for traders to understand why certain data or relationships are being latched onto.
The Financial Services Authority has been keeping a watchful eye on the development of black box trading, highlighting the risk of system failure leading to business interruption. This is a major issue, especially considering the great benefits of efficiency that new technology is bringing to the market.
UK Treasury minister Lord Myners has warned that companies could become the "playthings" of speculators due to automatic high-frequency trading, risking the destruction of the relationship between an investor and a company.
Risk of Over-Optimization
Over-optimization is a common pitfall in trading that can lead to a trading plan that looks good on paper but fails to perform in a live market. Traders who use backtesting techniques to optimize their systems may create systems that are carefully fitted to previous market price behavior but unreliable in live, current markets.
The problem of over-optimization can occur when traders create an excessive curve-fitting that produces a trading plan with unrealistic expectations. Some traders assume that a trading plan should generate 100% profitable trades without allowing room for drawdowns.
Concerns

The risks of computerized trading are a major concern for many experts.
Black box systems can be difficult to understand and may not always make intuitive sense to traders.
The Financial Services Authority has warned that systems failure can result in business interruption due to reliance on sophisticated technology and modeling.
Companies could become the "playthings" of speculators because of automatic high-frequency trading, according to UK Treasury minister Lord Myners.
Latency, or the delay in getting quotes to traders, is a technical problem that can have significant consequences.
Security is also a major issue, as seen in the case of Knight Capital Group's technology issue in 2012, which resulted in a loss of $440 million.
The Flash Crash of 2010, which saw the Dow Jones Industrial Average plunge 600 points, was contributed to by algorithmic and high-frequency trading.
Internet connectivity issues, power losses, and computer crashes can all result in errant orders and business interruption.
Frequently Asked Questions
Do algo trading really work?
Algorithmic trading can be profitable, as many professional traders and hedge funds use it to generate consistent profits. With the right strategy and execution, algo trading can be a viable option for achieving financial success
How profitable is algo trading?
Algo trading can be profitable, but its success depends on a solid understanding of financial markets and careful strategy development. With the right approach, algo trading can yield significant advantages over manual trading.
Is algo trading legal in US?
Yes, algo trading is legal in the US, regulated by agencies like the SEC, CFTC, and FINRA. Learn more about the rules and regulations governing algo trading in the US financial markets.
Sources
- https://www.investopedia.com/articles/active-trading/101014/basics-algorithmic-trading-concepts-and-examples.asp
- https://en.wikipedia.org/wiki/Algorithmic_trading
- https://corporatefinanceinstitute.com/resources/equities/algorithmic-trading/
- https://corporatefinanceinstitute.com/resources/career-map/sell-side/capital-markets/what-are-algorithms-algos/
- https://www.ig.com/en/trading-platforms/algorithmic-trading
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