Why Indicators Exist
Markets generate noise. Every day, thousands of stocks move up and down for reasons that range from meaningful (earnings beat expectations) to completely random (a large fund rebalanced its portfolio).
Technical indicators are mathematical tools designed to filter that noise and identify patterns with higher-than-random predictive value. They don't predict the future with certainty — nothing does — but they give you a systematic basis for decisions instead of relying on gut feelings or tips.
Here are three indicators that form the backbone of most algorithmic trading strategies.
Simple Moving Average (SMA)
What it is: The average closing price of a stock over a specific number of days.
The formula: Sum of closing prices over N days ÷ N
Example: A 50-day SMA for a stock trading at roughly $100 would be the average of its closing prices over the last 50 days.
Why it matters: Moving averages smooth out short-term price fluctuations and reveal the underlying trend. A rising 200-day SMA indicates a long-term uptrend; a falling one indicates a downtrend.
Two key uses:
- Trend identification: When a stock is trading above its 200-day SMA, the long-term trend is bullish. Below it, bearish.
- Dynamic support/resistance: Stocks often "bounce" off their major moving averages (50-day, 200-day) as buyers step in on dips.
Common SMA periods:
| Period | Use |
|---|---|
| 10-day | Very short-term momentum |
| 50-day | Medium-term trend |
| 200-day | Long-term trend benchmark |
WealthSignal's algo signals use SMA-based strategies (the SMA Crossover and Golden Cross) to generate systematic buy and sell signals.
Relative Strength Index (RSI)
What it is: A momentum oscillator that measures the speed and magnitude of recent price changes, scaled from 0 to 100.
The interpretation:
- RSI above 70: The stock is overbought — it may be due for a pullback
- RSI below 30: The stock is oversold — it may be due for a bounce
- RSI between 40-60: Neutral momentum
Why it matters: RSI helps identify when a trend may be exhausted. If a stock is in a strong uptrend but RSI reaches 85, that's a signal to look for an exit or at least not to add to the position.
A key insight about RSI: In strong uptrends, RSI can stay above 70 for extended periods without pulling back. In strong downtrends, it can stay below 30. Context matters — RSI works best when combined with trend analysis (like SMA) rather than used in isolation.
RSI Divergence: A powerful signal where price makes a new high but RSI doesn't. This "negative divergence" often precedes a reversal. Similarly, price making a new low while RSI rises (positive divergence) can signal a bottom.
The Golden Cross (and Its Opposite: The Death Cross)
What it is: A technical signal where a shorter-term moving average crosses above (or below) a longer-term moving average.
Golden Cross: The 50-day SMA crosses above the 200-day SMA. Widely considered a bullish signal — short-term momentum is accelerating above the long-term baseline.
Death Cross: The 50-day SMA crosses below the 200-day SMA. Considered a bearish signal — short-term weakness has persisted long enough to drag below the long-term trend.
Does it work? The historical data is mixed, but broadly supportive. Studies show the Golden Cross has positive predictive value over intermediate time horizons (3-6 months), though with plenty of false positives, particularly in choppy sideways markets.
The Golden Cross is most reliable when:
- Volume is above average on the crossover day
- The broader market is in a healthy uptrend
- The stock's fundamentals support the technical signal
WealthSignal's Golden Cross strategy automatically scans for crossover signals across the entire market so you don't have to monitor individual stocks manually.
Putting It Together: A Simple Strategy
Here's how these three indicators can combine into a complete trading strategy:
Buy signal (all three conditions must be true):
- Stock is trading above its 200-day SMA (long-term uptrend)
- RSI is between 40-60 (not overbought — room to run)
- 50-day SMA has recently crossed above 200-day SMA (momentum building)
Sell signal (any one condition triggers exit):
- RSI exceeds 75 (momentum exhausted)
- Stock closes below 200-day SMA (long-term trend broken)
- 50-day SMA crosses back below 200-day SMA (Death Cross)
This is a simplified version of what WealthSignal's algo strategies do. The platform runs these calculations automatically and alerts you when conditions are met.
Beyond the Basics
These three indicators are a foundation, not a complete system. Professional quant strategies layer in additional signals:
- MACD (Moving Average Convergence Divergence): Combines two moving averages to identify momentum shifts
- Bollinger Bands: Volatility-based bands that identify breakout potential
- Volume indicators: Confirm whether price moves have conviction behind them
- Earnings and macro filters: Avoid holding positions through earnings releases unless that's part of the strategy
The Right Way to Test a Strategy
The only way to know if an indicator-based strategy actually works is to test it against historical data. WealthSignal's backtesting tool lets you run any of the built-in strategies against years of market data, so you can see the actual performance — including Sharpe ratio, max drawdown, and win rate — before risking real money.
After backtesting, the next step is paper trading to test whether you can actually execute the strategy consistently over real market conditions.
The goal isn't to find a perfect strategy — there isn't one. The goal is to find a strategy you understand, can execute consistently, and whose risk metrics you're comfortable with. That's the foundation of every successful investor.