Momentum (MOM)

Momentum

What it measures

Momentum is the simplest possible momentum reading: the raw price change over a fixed lookback (default 10 periods) — today's close minus the close N bars ago. No smoothing, no normalization, just speed of price change in the security's own price units.

How readings are interpreted

Positive and rising: price is accelerating upward. Positive but falling: still rising, but losing steam. Crossing zero: the price is now below (or above) where it was N bars ago — a raw trend-change signal. Because it's unbounded and unnormalized, its absolute value only means something relative to the stock's own price level and volatility.

Conventional levels

Crossing above zero: price now higher than N bars ago — bullish
Crossing below zero: price now lower than N bars ago — bearish
Rising Momentum with rising price: healthy trend
Falling Momentum with rising price: early warning of exhaustion
Extreme readings only meaningful relative to the stock's own recent history — there's no universal threshold

Where it works, and where it does not

Because it's raw and unnormalized, Momentum is not comparable across different stocks or even across different time periods for the same stock (a 10-point move means something very different for a $20 stock than a $2,000 stock). It's most useful as a same-stock, same-timeframe trend-change trigger, not for cross-ticker screening.

Commonly read alongside

ROC: Nearly identical signal in percentage form — ROC is generally the more useful version for comparing across tickers
RSI: Momentum zero-cross + RSI crossing 50 = confirmed trend shift
Volume: Momentum acceleration on rising volume is a stronger signal than on falling volume

Known limitations

Not comparable across tickers or price levels — a raw Momentum screen will just surface high-priced, volatile names
Very noisy on short lookbacks; smooth with a longer period or prefer ROC for practical use
Doesn't account for the path price took to get there — a straight-line move and a choppy round-trip can show the same Momentum value

In practice

Prefer ROC over raw Momentum for anything involving comparison across stocks
Use the zero-line cross as a simple trend-change trigger on a single ticker you already track
A longer moving average filter is the conventional way to screen out minor zero-crosses
Works best paired with volume — accelerating price + accelerating volume is a much stronger combination than either alone

Plot it yourself. Add this indicator to a chart, change every parameter and watch the line move, then backtest how the rule would have behaved on historical data — free on the S&P 500 ETF, no card.

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This is reference material, not advice. It describes what each indicator measures and how its readings are conventionally interpreted. Nothing here is a recommendation to buy or sell anything, and no indicator predicts future prices. GU Analyser is an analytical tool — no money is ever traded here.