Trend & directionKnow Sure Thing · KST
Martin Pring's momentum oscillator that blends four smoothed rates of change into one weighted line.
Works best in trending marketsEngine-computed on a fixed sample series
What it is
The Know Sure Thing, or KST, is a momentum oscillator built by the veteran analyst Martin Pring, who gave it a slightly tongue-in-cheek name to reflect his confidence in its smoothed, multi-cycle design. The core insight is that momentum operates on several time cycles at once, and no single rate-of-change measurement captures all of them, so the KST blends four different rate-of-change calculations into one weighted line. By combining short, intermediate, and longer momentum cycles, it aims to give a fuller and smoother picture of the market's momentum than any single oscillator. It moves above and below a zero line and has a signal line, making it feel familiar to anyone who has used the MACD. For a beginner, the KST is a momentum gauge that deliberately listens to several rhythms of the market simultaneously instead of just one.
How it is calculated
The KST starts by computing the rate of change, the percentage price change over a lookback, for four different periods that represent different cycles, commonly around ten, fifteen, twenty, and thirty bars. Each of those raw rate-of-change series is then smoothed with its own moving average to strip out noise. The four smoothed values are combined in a weighted sum, with the longer-term cycles given progressively heavier weights, typically one, two, three, and four, so that the slower, more meaningful trends dominate the final reading. That weighted sum is the KST line, and a nine-period moving average of it forms the signal line. Pring published different parameter sets tuned for short-term, intermediate-term, and long-term analysis, so the exact numbers vary with the intended horizon.
Reading it, step by step
The most-watched signal is the KST crossing its signal line: a cross above is bullish and a cross below is bearish, and because the KST is heavily smoothed these crosses are relatively clean. The zero line separates net-positive momentum above from net-negative momentum below, so a KST rising through zero confirms that the blended momentum has turned genuinely positive, a slower but more reliable signal than the signal-line cross. The direction and slope of the KST show whether momentum is accelerating or decelerating. Divergence between the KST and price, where price makes a new high but the KST makes a lower high, is a valuable early warning that the multi-cycle momentum behind the trend is weakening. Because it aggregates several cycles, extreme readings are less about fixed overbought levels and more about the KST's position relative to its own recent range.
Best timeframes and settings
One of the KST's strengths is that Pring designed explicit variants for different horizons, so there are recognized parameter sets for short-term daily trading, intermediate-term swing analysis, and long-term monthly cycle work. On weekly and monthly charts the KST is a favorite of position traders and cycle analysts for gauging major turning points. The default daily construction suits swing traders looking for cleaner momentum crossovers than a raw rate of change provides. Because four smoothed rate-of-change series are stacked, the indicator inherently lags, and shortening the periods to sharpen responsiveness reintroduces the noise the smoothing was meant to remove. The trade-off is fundamental: the KST buys smoothness and multi-cycle perspective at the price of lag, so it is better suited to catching the meat of a trend than its exact turn.
When and where to use it
The KST is a trend and momentum tool that works best in markets that move in identifiable cycles and sustained trends, which is why Pring, a cycle theorist, favored it for longer-horizon analysis. It applies across asset classes, from stock indices to commodities to individual equities, and is especially valued on weekly and monthly data for strategic positioning. It is less suited to fast, choppy intraday scalping, where its lag becomes a liability. Use it when you want a smoothed, big-picture read on momentum that filters out the jitter of a single rate-of-change line. Avoid leaning on it for precise reversal timing, since its heavy smoothing means it confirms turns after they are underway rather than calling them at the extreme.
Strategies that use it
The standard strategy trades signal-line crossovers in the direction of the larger trend: go long when the KST crosses above its signal line while the broader trend is up, and exit or reverse on the opposite cross. A higher-conviction, slower approach uses zero-line crossings as the trigger, buying when the KST crosses above zero to confirm net-positive momentum and selling when it drops below, accepting later entries for fewer false signals. A divergence strategy watches for the KST failing to confirm a new price extreme and uses that as an early warning to tighten stops or prepare for a reversal. Because Pring built timeframe-specific variants, a powerful method aligns a long-term KST for the major trend with a short-term KST for timing, only taking short-term signals that agree with the long-term direction.
Combining it with other indicators
The KST combines naturally with a trend filter such as a long moving average, which confirms the direction in which its crossovers should be traded. Pairing it with other momentum tools like the MACD or the rate of change can corroborate a momentum shift, and Pring himself often used the KST alongside price-pattern and trendline analysis. Support and resistance give KST divergences a location to matter, since a bearish divergence at major resistance is more actionable than one in open space. On longer horizons, cycle analysis and the KST reinforce each other because both are concerned with the rhythm of the market. The overarching idea is to use the KST for the smoothed momentum read and to supply trend direction and price levels from independent tools.
Where it fails
The KST's defining weakness is lag: four smoothed rate-of-change series stacked together mean the indicator turns noticeably late at sharp reversals, so it is poor at catching V-shaped bottoms and tops. Its many parameters, four periods plus four smoothing lengths plus the signal line, make it easy to over-optimize to historical data, producing settings that look brilliant in a backtest and fail in real trading. In choppy, trendless markets the signal-line crossovers still whipsaw despite the smoothing. Beginners sometimes expect the confident name to mean confident signals and are surprised by its lateness. The way to work with it is to accept that it is a trend-confirmation and cycle tool rather than a reversal caller, to lean on the slower zero-line signals and divergence for reliability, and to resist the temptation to curve-fit its many inputs.
A worked example
On a weekly chart of an index fund, price has been recovering from a bear market and the long-term KST, deeply negative for months, begins to curl upward. When the KST crosses above its signal line while still below zero, you note a promising early sign but wait for stronger confirmation. Several weeks later the KST pushes above the zero line, confirming that the blended multi-cycle momentum has turned net-positive, and price is holding above its rising fifty-week moving average. You enter a long position near the current price of two hundred and twenty with a stop below the recent swing low at two hundred and five. Over the following months the KST stays above zero and above its signal line as the index climbs to two hundred and seventy, and you hold, exiting only when the KST finally crosses back below its signal line, having captured the bulk of the new bull leg.