3.1 Moving Averages

Understand the most universally-used indicator family — moving averages. How they're calculated, how they're used, and where they fail.

Layer 3: Technical Indicators — Chapter 1 Goal: Understand the most universally-used indicator family — moving averages. How they're calculated, how they're used, and where they fail.

The Core Idea

A moving average (MA) is the average price over a specified number of periods, recalculated each new period. As new prices come in and old ones drop off, the average "moves."

Moving averages smooth out noise to reveal the underlying trend, act as dynamic support/resistance, and serve as signal lines for entries and exits.

They are the single most widely-used indicator in technical analysis. Understanding them well is non-negotiable.

Why Use Moving Averages?

Three main use cases:

1. Trend Identification

Price above a rising MA = uptrend
Price below a falling MA = downtrend
Price oscillating around flat MA = range

2. Dynamic Support and Resistance

In uptrends, MAs often act as support (price pulls back, bounces off the MA)
In downtrends, MAs often act as resistance

3. Signal Generation

Crossovers (price crossing an MA, or MAs crossing each other)
Slope changes (MA rolling over)

Simple Moving Average (SMA)

The most basic type.

Formula

SMA = (P₁ + P₂ + P₃ + ... + Pₙ) / n

Where P = price (usually closing price) and n = number of periods.

Example: 5-day SMA of AMD

Closes: $198, $200, $201, $199, $202 SMA(5) = ($198 + $200 + $201 + $199 + $202) / 5 = $200

Next day closes at $204: New 5-day window: $200, $201, $199, $202, $204 SMA(5) = $1,006 / 5 = $201.20

The "moving" part: each day, the oldest price drops off and the newest is added.

Properties

Treats all periods equally
Slow to react to new information
Smooth, easy to interpret
Best for: trend identification on higher timeframes

Exponential Moving Average (EMA)

A weighted version that gives more weight to recent prices.

Formula

EMA = (Today's Close × k) + (Yesterday's EMA × (1 - k))

Where k = 2 / (n + 1)

For a 20-period EMA: k = 2/21 ≈ 0.095, meaning today's close gets ~9.5% weight, while yesterday's EMA (which contains the history) gets ~90.5%.

Properties

More responsive to recent price changes
Reacts faster to new trends
Slightly noisier than SMA
Best for: shorter timeframes and active trading

EMA vs. SMA: Which to Use?

EMA: Default for active traders. Faster signals.
SMA: Default for long-term investors. Smoother signals.

For swing trading: EMA is the better default.

Weighted Moving Average (WMA)

Another weighted variant. Most recent prices get linearly higher weights.

Formula

WMA = (P₁×1 + P₂×2 + P₃×3 + ... + Pₙ×n) / (1 + 2 + 3 + ... + n)

Properties

Between SMA and EMA in responsiveness
Less popular than EMA
Rarely worth using over EMA for most purposes

Verdict: Use EMA. Skip WMA.

Common Periods and What They Represent

Period	Common Use
9 EMA	Very short-term momentum (day traders)
20 EMA	Short-term trend (the most popular for swing trading)
50 EMA / 50 SMA	Intermediate trend (institutional reference)
100 SMA	Long-term trend
200 SMA	THE long-term trend (the most-watched MA in finance)

Why These Specific Periods?

20 ≈ 1 month of trading days
50 ≈ 10 weeks ≈ 1 quarter
100 ≈ 20 weeks
200 ≈ 40 weeks ≈ ~1 year

These match natural cycles in business and investment timeframes.

The 200-Day Moving Average

This is special. Watched by:

Every institutional trader
Every fund manager
Most CNBC commentators
Most algorithms

When a stock crosses its 200-day MA, headlines are written. Buying/selling cascades. The level itself becomes self-fulfilling.

As a swing trader: never trade against the 200-day MA. If price is above it, lean long. Below it, be cautious or short.

Moving Averages as Dynamic Support/Resistance

How It Works

In an uptrend, traders see the MA as "fair value." When price dips toward the MA:

Buyers re-enter (they missed the rally, now have a "value" entry)
Algorithms buy automatically
Price bounces off the MA

Example: 20-day EMA Pullback

AMD trending up, above 20 EMA for weeks
Pulls back, touches 20 EMA at $200
Buying volume increases at $200
Price bounces back up

This is the basis for one of your three swing setups (pullback to MA).

Strength Hierarchy

Bounces from 20 EMA = mild support (common)
Bounces from 50 EMA = stronger support (institutional)
Bounces from 200 SMA = strongest support (existential level)

Crossovers

Two main types:

1. Price Crosses MA

Price crosses above MA = potential bullish signal
Price crosses below MA = potential bearish signal

2. MA Crosses MA

This is where "Golden Cross" and "Death Cross" come from.

Golden Cross

Short-term MA (e.g., 50-day) crosses ABOVE long-term MA (e.g., 200-day)
Considered bullish
Often marks the start of major uptrends
Lagging signal — the trend is already underway when it triggers

Death Cross

Short-term MA crosses BELOW long-term MA
Considered bearish
Often marks the start of major downtrends
Also lagging

Reality Check

These crossovers occur on closing prices in their windows
They're slow signals
They give back significant gains in choppy markets
Best used for trend confirmation, not entry timing

The "Stacked MA" Pattern

A very useful structural read:

Bullish Stack

Price > 20 EMA > 50 EMA > 100 SMA > 200 SMA
All MAs sloping up
Indicates strong, durable uptrend
Highest-quality setups exist in this regime

Bearish Stack

Price < 20 EMA < 50 EMA < 100 SMA < 200 SMA
All MAs sloping down
Strong, durable downtrend

Tangled MAs

MAs crossing each other repeatedly
No clear direction
Ranging market
Avoid trend-following strategies here

Bullish bias
Stronger slope = stronger trend

Falling MA

Bearish bias
Stronger slope = stronger trend

Flat MA

Neither bullish nor bearish
Often signals trend exhaustion or range
Don't initiate trend-following positions when the MA is flat

Convergence happens during low-volatility consolidation
After consolidation, a breakout becomes inevitable
The pinch is a "compression" of price

Trading Application

Watch for 20, 50, 100 EMAs converging
Combine with tight price range
Wait for breakout direction
Volume confirms

20 EMA (short-term trend)
50 EMA (intermediate trend)
200 SMA (long-term reference)

That's it. No more.

What You'll Look For

Are they stacked?
What's the slope of the 20 and 50?
Is price near a key MA (potential bounce)?

MA-Based Setups (Preview)

Setup 1: Pullback to 20 EMA in Uptrend

20 EMA rising
Price above 50 EMA
Pullback to 20 EMA
Bullish reversal candle on rising volume
Entry: confirmation candle
Stop: below 20 EMA
Target: prior high

Setup 2: 50 EMA Bounce

Stronger pullback, deeper retracement
Same logic but at 50 EMA
Larger position size justified (better R:R)

Setup 3: Trend Resumption After 20/50 Cross

20 EMA crosses back above 50 EMA after a brief consolidation
Indicates trend has resumed
Higher conviction continuation trade

A Mental Model

A moving average is like a car's dashboard:

It doesn't tell you where the road is
It tells you your average speed over recent time
Sudden changes (slope) signal acceleration or deceleration
It's lagging by design — that's the value (smoothing out noise)
You don't drive looking only at the dashboard, and you don't trade looking only at MAs

MAs are filters, not signals on their own.

Practical Takeaways

EMA over SMA for active trading. Faster response.
Stick to 20, 50, 200 for swing trading.
Stacked MAs = strong trend. Trade with the stack.
Slope > position. A rising MA is bullish even if price is momentarily below it.
200-day MA is sacred. Trade in its direction.
Crossovers are lagging. Use for confirmation, not entry timing.
MAs are filters, not strategies. Combine with S/R, patterns, and volume.

Quick Self-Check

Before moving to 3.2, you should be able to answer:

What's the formula for SMA?
How is EMA different from SMA?
What does the 200-day SMA represent?
What's the difference between a Golden Cross and a Death Cross?
What does a "stacked MA" pattern indicate?
Why does MA slope matter as much as position?
What's the recommended MA setup for swing trading?

Next: 3.2 Momentum Oscillators (RSI, Stochastic)