Special K

What is the Special K?

The Special K is a momentum indicator developed by Martin Pring that combines short-term, intermediate, and long-term smoothed rate-of-change measurements into a single unbounded line. It extends Pring's Know Sure Thing, which blends four smoothed ROC inputs; the Special K stacks twelve of them, spanning lookbacks from days to roughly two years of daily data, each smoothed and weighted so that longer horizons contribute more.

Pring's rationale is that a market's price action is the sum of many cycles operating at once. Any single-lookback momentum tool captures one slice; summing weighted, smoothed ROCs across the spectrum approximates the whole. The design goal, as Pring describes it, is a line whose peaks and troughs tend to coincide with, rather than lead or lag, the primary trend turns of the price series itself. That intent is distinctive: many long-horizon momentum tools, such as the Coppock Curve, are built to confirm turns after the fact rather than to track them as they happen.

Traders care because the Special K reframes momentum as a trend-identification device. Instead of hunting overbought and oversold extremes (the line is unbounded and has none), analysis focuses on the direction of the line, its position relative to a smoothing of itself, and divergences at major turns. It is a slow, big-picture instrument intended for position traders and asset allocators, not a timing tool for short swings.

How it's calculated

The Special K is a weighted sum of twelve smoothed rate-of-change terms. The commonly published daily formulation is:

The first four terms are the components of Pring's short-term KST; the middle four and last four approximate his intermediate and long-term KSTs on daily data, so the Special K is effectively the three KST horizons summed.

The very long lookbacks mean the indicator needs several years of data before it is fully formed, and early values are unreliable.

Weekly and monthly adaptations exist that rescale the lookbacks; parameter details vary by platform.

How traders use it

• To locate primary trend turns: because the line is designed to peak and trough near the price series' own major turning points, a decisive reversal in the Special K is read as evidence the primary trend has turned.
• With a signal smoothing: Pring suggests comparing the Special K to a moving average of itself and watching for crossovers plus a break of the line's own trendline as a combined confirmation.
• For divergence at major tops and bottoms: a new price extreme against a flatter Special K warns that the multi-horizon momentum backdrop is deteriorating.
• As an allocation input rather than a trade trigger: the tool suits monthly and weekly decision cycles; its signals are far too slow for short-term trading.
• With honest limits: the coincident-turn property is a design intention that holds often but not always, whipsaws occur in extended sideways markets, and the long lookbacks make early-history readings meaningless.

Special K vs. related long-horizon momentum tools