Algorithmic Trading Basics — Rules Place Orders Instead of People
A world where, instead of a person watching a screen and clicking, a computer buys and sells on its own by preset rules. Today a substantial share of trading happens this way.
What algorithmic trading is
Algorithmic trading (algo trading) is a method in which a computer program, not a person, places orders automatically according to predetermined rules.
The rules may be technical indicators like moving averages or RSI, or statistical models like mean reversion or arbitrage. When market conditions match the rules, the program executes buys and sells on its own.
The 'execution algorithms' like VWAP and TWAP covered later are also a branch of algorithmic trading.
How it runs — 4 stages
Typical algorithmic trading goes through the following stages.
① Strategy definition: set the rules for under what conditions to buy and sell. ② Coding: translate the rules into a program (Python, etc.). ③ Backtest: verify performance, drawdown, and accuracy on historical data. ④ Live deployment: monitor the market in real time and place orders automatically when conditions are met.
The big difference from human trading is that it excludes emotion and executes consistently.
The risks behind the convenience
Automation is powerful but carries its own risks.
First is overfitting. Rules fitted only to past data collapse easily in the actual future.
Second is system and connectivity errors. A bug or network failure can trigger a large loss in an instant. There are cases like the 2010 'Flash Crash,' where algorithms became entangled and the market plunged within minutes.
Third is that even when the rule is wrong, it keeps executing without emotion. In a situation where a person would have stopped, the program can grow the loss.
An algorithm merely executes rules fast and consistently; it does not guarantee that the rule itself is correct.
This article does not recommend any particular trading strategy or program. You must understand together the overfitting where rules that looked good in a backtest fail in live trading, and the risk of sudden losses from system errors.
Frequently Asked Questions
Q. Does algorithmic trading mean you won't lose money?
Not at all. An algorithm merely executes rules while excluding emotion; if the rule is wrong, losses pile up automatically too. In particular, an overfitted strategy tailored only to the past collapses easily in live trading.
Q. Can individuals do algorithmic trading too?
It is technically possible, but there are many walls to clear such as data quality, fees, system stability, and overfitting verification. It is also a practical limit that it is hard to beat professional institutions in the speed race.
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📋 Results are based on historical data; past returns do not guarantee future returns.
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