Technical Analysis Basics: RSI, MACD & Bollinger Bands
Learn the essential tools of technical analysis using price and volume data. Practical applications of RSI, MACD, Bollinger Bands, and moving averages.
1What Is Technical Analysis?
Technical analysis is a method of evaluating investments by analyzing historical price and volume data to predict future price movements. Unlike fundamental analysis — which examines a company's financial statements, business model, and competitive advantage — technical analysis focuses on chart patterns and mathematical indicators.
Technical analysis rests on three core assumptions. First, the market discounts everything (all information is reflected in the price). Second, prices move in trends. Third, history repeats itself (past patterns tend to recur).
- Trend: The general direction of price movement. Classified as uptrend (higher highs and higher lows), downtrend (lower highs and lower lows), or sideways/range-bound.
- Support: A price level where buying pressure prevents further decline. Previous lows often become support levels.
- Resistance: A price level where selling pressure prevents further rise. Previous highs often become resistance levels.
Important: Technical analysis is a useful tool for short-term trading, but no indicator can predict the future with 100% accuracy. Always combine it with fundamental analysis and set stop-loss levels before entering trades.
2Moving Averages (MA)
A Moving Average (MA) is a line created by averaging a stock's price over a specific number of days. It smooths out short-term price fluctuations to reveal the underlying trend, making it the most fundamental tool in technical analysis.
| Moving Average | Period | Usage |
|---|---|---|
| 5-day MA | 1 week (short-term) | Day trading, ultra-short-term trends |
| 20-day MA | 1 month (short-to-mid) | Swing trading, short-term trend confirmation |
| 50-day MA | ~2.5 months (mid-term) | Medium-term trend, institutional reference |
| 100-day MA | ~5 months (mid-to-long) | Often called the "sentiment line" |
| 200-day MA | ~1 year (long-term) | The "lifeline" — key for long-term investors |
Golden Cross vs. Death Cross
- Golden Cross: When a shorter-term MA crosses above a longer-term MA. Signals a potential uptrend — considered a buy signal. Example: 50-day MA crossing above the 200-day MA.
- Death Cross: When a shorter-term MA crosses below a longer-term MA. Signals a potential downtrend — considered a sell signal.
* Moving averages are lagging indicators, meaning signals appear after the actual trend reversal. Always confirm with other indicators.
3RSI (Relative Strength Index)
The RSI is a momentum oscillator that compares the magnitude of recent gains to recent losses over a specified period (typically 14 days) to determine whether a stock is overbought or oversold. It ranges from 0 to 100.
- RSI above 70 = Overbought: The stock has risen rapidly in the short term. A pullback or correction is more likely, making it a zone to consider selling or taking profits.
- RSI below 30 = Oversold: The stock has fallen sharply in the short term. A bounce or recovery is more likely, making it a zone to consider buying.
- RSI around 50: Neutral zone with no clear directional bias.
Practical Example
Imagine a blue-chip stock drops sharply and its RSI falls to 25. Since an RSI below 30 indicates oversold conditions, a rebound becomes statistically more likely. Historical data shows that after RSI drops below 25, stocks often bounce within 1-2 weeks. However, in strong downtrends, RSI can remain in oversold territory for extended periods — always confirm with volume and other indicators.
4MACD
MACD (Moving Average Convergence Divergence), developed by Gerald Appel in 1979, uses the difference between two exponential moving averages (EMAs) to identify trend direction, strength, and potential reversal points. It remains one of the most widely used technical indicators worldwide.
- MACD Line: 12-day EMA minus 26-day EMA. Shows the difference between short-term and long-term momentum.
- Signal Line: 9-day EMA of the MACD line. Acts as a smoothed reference line for the MACD.
- Histogram: Bar chart showing the difference between the MACD line and signal line. Positive bars indicate bullish momentum; negative bars indicate bearish momentum.
MACD Trading Signals
- Bullish Crossover (Buy): MACD line crosses above the signal line. Especially powerful when it occurs below the zero line.
- Bearish Crossover (Sell): MACD line crosses below the signal line. Especially powerful when it occurs above the zero line.
- Divergence: When the stock makes a new high but MACD does not — this bearish divergence suggests a potential trend reversal downward. The inverse (bullish divergence) also applies.
5Bollinger Bands
Bollinger Bands, developed by John Bollinger, consist of a moving average centerline flanked by upper and lower bands set at standard deviations from the mean. They provide a visual representation of volatility and help identify overbought/oversold conditions and volatility breakout opportunities.
- Middle Band: 20-day Simple Moving Average (SMA). Represents the trend center.
- Upper Band: Middle Band + (2 x Standard Deviation). Price approaching the upper band may indicate overbought conditions.
- Lower Band: Middle Band - (2 x Standard Deviation). Price approaching the lower band may indicate oversold conditions.
Key Bollinger Band Strategies
- The Squeeze: When the bands narrow significantly, volatility is extremely low — a big move (up or down) is likely imminent. This is one of the most reliable Bollinger Band signals.
- Band Expansion: After a significant price movement, bands widen — confirming trend strength.
- Band Walking: During strong trends, prices can "walk" along the upper (or lower) band for extended periods. In this case, touching the band does NOT automatically mean overbought/oversold.
6Practical Tips & Warnings
When applying technical analysis tools in practice, always follow these principles. No single indicator is perfect — combining multiple tools and managing risk is essential.
- Combine Multiple Indicators: Use RSI + MACD, or Moving Averages + Bollinger Bands together. When multiple indicators give the same signal simultaneously, the probability of success increases significantly.
- Always Confirm with Volume: Price movements without corresponding volume are unreliable. There's a saying: "Volume precedes price." A breakout on high volume is far more trustworthy than one on low volume.
- Set Stop-Losses Before Entry: Always define your exit point before entering a trade. A common approach is to set stop-losses at -3% to -5% from entry price, or below a key support level.
- Backtesting: Before risking real money, test your strategy against historical data. While past performance doesn't guarantee future results, backtesting helps validate the basic effectiveness of your approach.
Technical analysis is a reference tool for investment decisions, not a crystal ball. No technical indicator can predict the future with certainty. Final investment decisions and their outcomes are entirely the investor's responsibility. Always prioritize risk management above all else.