Coppock Curve Indicator: The 60-Year-Old Buy Signal That Still Works

Most technical indicators are born from math. The Coppock Curve was born from a conversation about grief.

Edwin Sedgwick Coppock was an economist and the founder of Trendex Research in San Antonio, Texas. In the late 1950s, the Episcopal Church approached him with a specific question: could he build a tool that would help long-term investors identify the right moment to buy back into the stock market after a major decline? The Church managed endowment funds and wanted a systematic, unemotional approach to timing their re-entry after bear markets.

Coppock agreed to try. But he needed a starting point — some way to estimate how long a market downturn typically lasts before sentiment genuinely shifts. Rather than digging through statistical tables, he asked the Episcopal bishops a different question entirely: how long does it take a person to grieve a significant loss? Their consensus was 11 to 14 months. Coppock took that human insight and translated it directly into his formula. The 14-period and 11-period Rate of Change parameters that define the indicator to this day are not the result of optimization or curve-fitting. They are the mathematical expression of a mourning period.

There is something almost poetic about that. Markets crash, investors panic, portfolios get destroyed — and Coppock's thesis was that the recovery process mirrors the psychology of bereavement. First comes shock, then denial, then gradual acceptance, and finally the willingness to move forward. The indicator does not try to catch the exact bottom. Instead, it waits for the emotional cycle to complete — for market participants to finish mourning their losses and start buying again with conviction.

Coppock published his work in Barron's on October 15, 1962, calling it the "Trendex Model." The name "Coppock Curve" came later, assigned by the trading community that adopted it. The original design was intentionally narrow: monthly data only, applied to the S&P 500 and Dow Jones Industrial Average. Coppock was not trying to build a universal oscillator. He was building a bear-market-is-over detector for equity indices, and he was very clear about that scope.

What makes this origin story more than just a charming anecdote is that it actually explains the indicator's strengths and limitations. The mourning-period logic works well for equity markets because stock market bottoms tend to be sharp, emotional events — capitulation selling followed by a gradual recovery of confidence. Commodity markets, by contrast, tend to form rounded bottoms that develop over longer, less dramatic timeframes. The grieving metaphor fits stocks naturally; it fits copper and wheat less well. Coppock himself acknowledged this, and it is why the indicator was never marketed as a general-purpose tool.

The fact that an indicator designed in the late 1950s, based on a conversation with clergymen rather than a statistical regression, has remained relevant for over 60 years tells you something important about what drives markets. Technology changes, regulations change, trading speed changes — but the human emotional cycle that governs how investors respond to losses has barely budged. Fear and recovery still follow the same rhythm they followed when Coppock first picked up the phone to call his bishop.

The Coppock Curve has one of the cleanest formulas in technical analysis. No complex algebra, no iterative smoothing tricks, no hidden constants. Three steps, three parameters, done.

Step 1 — Calculate two Rate of Change values

The Rate of Change (ROC) measures how much price has moved over a specific number of periods, expressed as a percentage. The formula is straightforward:

ROC = ((Current Close - Close N periods ago) / Close N periods ago) x 100

The Coppock Curve uses two ROC calculations simultaneously:

• A 14-period ROC capturing longer-term momentum
• An 11-period ROC capturing slightly shorter-term momentum

On a monthly chart with default settings, the 14-period ROC looks back roughly 14 months, and the 11-period ROC looks back 11 months. If the S&P 500 closed at 4,500 today and was at 4,000 fourteen months ago, the 14-period ROC would be +12.5%. If it was at 4,100 eleven months ago, the 11-period ROC would be +9.76%.

Step 2 — Add the two ROCs together

This is literally addition. Take the 14-period ROC value and add it to the 11-period ROC value. In our example: 12.5 + 9.76 = 22.26. This raw sum captures combined momentum across both lookback windows. When both ROCs are positive, the sum is strongly positive. When both are negative, the sum is deeply negative. When they disagree — one positive, one negative — the sum reflects the balance of power between the two timeframes.

The dual-ROC approach is what gives the Coppock Curve its stability. A single ROC line is noisy, prone to whipsawing above and below zero on minor price fluctuations. By summing two ROC values with different lookback periods, the indicator requires momentum to be consistent across both timeframes before producing a strong reading. A one-month spike in prices might push the 11-period ROC sharply higher, but if the 14-period ROC is still negative from a deeper decline, the sum stays muted. This natural filtering effect is baked into the calculation before any smoothing even happens.

Step 3 — Smooth the sum with a 10-period Weighted Moving Average

The raw ROC sum still has sharp edges. The 10-period WMA smooths those edges into a curve that is easier to read visually and generates cleaner signals. Unlike a Simple Moving Average that treats all data points equally, the WMA assigns progressively more weight to recent values. In a 10-period WMA, the most recent data point gets a weight of 10, the next gets 9, then 8, and so on down to 1 for the oldest point. The weighted sum is divided by 55 (which is 10 + 9 + 8 + ... + 1).

This weighting scheme means the Coppock Curve responds to fresh momentum shifts faster than an SMA-smoothed version would, while still filtering out random noise. The most recent ROC sum has roughly ten times the influence of the oldest ROC sum in the window.

The complete formula in one line:

Coppock Curve = WMA(10) of [ROC(14) + ROC(11)]

Reading the output

The Coppock Curve is unbounded — it has no fixed ceiling or floor like RSI's 0-100 range. The critical reference point is the zero line. Positive readings mean the combined momentum over both lookback periods is net bullish. Negative readings mean net bearish momentum. The magnitude tells you how strong that momentum is, but the direction of the curve — whether it is rising or falling — matters more for signal generation than the absolute value.

During a bear market, you will see the curve plunge deep into negative territory, often reaching -15 to -30 on major indices. The recovery process is visible as the curve gradually bends upward, even while still negative. That upward bend in negative territory is the earliest signal the indicator produces — the equivalent of Coppock's grieving process beginning to resolve. The actual zero-line cross confirms the recovery but arrives later, after the initial healing has already begun.

One common misconception: traders sometimes expect the Coppock Curve to oscillate symmetrically around zero like a traditional oscillator. It does not. Because equity markets have a long-term upward bias, the curve spends more time in positive territory than negative. Readings of +20 to +40 during bull markets are normal and do not automatically signal overbought conditions. The indicator was not designed to identify tops — Coppock specifically built it as a bottom-finding tool.

Coppock designed his indicator with a single purpose in mind, and the signal rules reflect that simplicity. The classic buy signal has two components that must both be present:

1. The Coppock Curve must be below the zero line (negative territory)
2. The curve must turn upward — that is, the current reading must be higher than the previous reading

That's it. No overbought thresholds, no divergence requirements, no moving average crossovers. When the curve is below zero and starts rising, the mourning period is ending and it is time to consider buying. Coppock was refreshingly honest about the other side of the trade: he did not design sell signals. The indicator was a buy-the-bottom tool, full stop.

Now, modern traders have expanded beyond Coppock's original rules, and there are several signal variations worth understanding.

The direction-change signal (earliest)

This is Coppock's original: the curve turns upward while still in negative territory. It fires before the zero-line cross, sometimes weeks or months ahead of it. On the S&P 500 monthly chart during the 2008-2009 financial crisis, the Coppock Curve bottomed in February 2009 and began turning upward in March 2009 — almost perfectly coinciding with the actual market bottom. However, the curve was still deep in negative territory at that point, around -25. Traders acting on this early signal captured the very beginning of the recovery, but they also needed strong conviction to buy when the indicator was still showing deeply negative momentum.

The zero-line crossover signal (confirmed)

When the curve crosses from negative to positive territory, it confirms that net momentum has fully shifted to bullish. This signal arrives later than the direction change but carries higher confidence. During the 2009 recovery, the zero-line cross did not occur until late 2009, by which time the S&P 500 had already recovered roughly 50% from its March low. The tradeoff is classic: early entry with more risk versus late entry with more confirmation.

The sell signal (unofficial but useful)

Coppock never intended a sell signal, but many analysts now use the inverse: the curve turns downward from positive territory or crosses below zero. The February 2001 downward cross preceded most of the dot-com bear market. The June 2008 downward cross got investors out before the worst of the financial crisis. These sell signals have historically been effective at avoiding the deepest drawdowns, even though they occasionally trigger during minor corrections that quickly reverse.

The divergence signal (advanced)

When price makes a new low but the Coppock Curve prints a higher low, bullish divergence suggests that the rate of decline is slowing even though prices are still falling. On weekly and monthly charts, this divergence pattern has preceded several major market turns. The divergence signal is not part of Coppock's original framework, but it leverages the same underlying logic: momentum is recovering before price visibly confirms it.

Signal frequency — the patience problem

On monthly charts, which is where the Coppock Curve was designed to live, signals are rare. The Dow Jones Industrial Average has generated roughly 15 buy signals since 1950 — that is about one every five years. If you are the kind of trader who needs action every week, this indicator will drive you to distraction. But that rarity is a feature, not a bug. Each signal represents a genuine shift in long-term momentum, not a minor fluctuation.

Reducing false signals with confirmation

The most effective approach treats the Coppock signal as a necessary-but-not-sufficient condition. When the curve turns upward from negative territory, add a second filter before entering: price must close above a key moving average (the 10-month SMA is a popular choice), or a separate momentum indicator like MACD must confirm the bullish shift. This dual-confirmation approach misses the absolute bottom but dramatically reduces the chance of entering during a bear market rally that fails.

One important caveat about the zero line

A brief dip below zero followed by an immediate recovery — what some traders call a "zero-line kiss" — is a lower-quality signal. The strongest buy signals occur after the curve has spent several months deep in negative territory (readings of -10 or lower on monthly equity indices), forming a clear U-shaped bottom before rising back toward zero. The depth and duration of the negative reading correlate with the significance of the subsequent buy signal. A shallow dip to -2 that bounces back is noise; a plunge to -25 that gradually curves upward is a major trend reversal developing in real time.

Edwin Coppock designed his indicator for monthly stock index charts, period. Everything about it — the mourning-period parameters, the WMA smoothing, the zero-line logic — was calibrated for markets that crash sharply and recover gradually over months or years. So what happens when you pull it off the monthly S&P 500 chart and drop it onto a daily EUR/USD chart? Short answer: it still works, but you need to understand what changes and what doesn't.

The timeframe conversion math

The straightforward approach to adapting the Coppock Curve for shorter timeframes is proportional scaling. One month contains roughly 4.33 weeks or 21-22 trading days. To maintain the same effective lookback on a weekly chart, multiply all parameters by 4.33:

• 14-month ROC becomes approximately 60-week ROC
• 11-month ROC becomes approximately 48-week ROC
• 10-month WMA becomes approximately 43-week WMA

For daily charts, the conversion yields even larger numbers: a 294-day ROC, 231-day ROC, and 210-day WMA. These settings preserve the original curve's shape and behavior on lower timeframes, but they create an extremely slow indicator on a daily chart — signals may take months to develop, which defeats the purpose of switching to daily data in the first place.

The practical shortcut: compressed parameters

Most traders who use the Coppock Curve on daily or weekly charts do not use the proportional conversion. Instead, they compress the parameters to generate more frequent signals. Popular configurations include:

• Daily chart (swing trading): ROC 20, ROC 10, WMA 10 — a common choice that produces signals every few weeks rather than every few months. This is the setting StockCharts recommends for daily analysis.
• Daily chart (position trading): ROC 14, ROC 11, WMA 10 — the default monthly parameters applied directly to daily data. Signals are infrequent but high-quality for multi-week position trades.
• Weekly chart: ROC 14, ROC 11, WMA 10 — the defaults work reasonably well on weekly charts without modification, producing signals roughly quarterly.

The tradeoff is always the same: shorter parameters produce more signals with more noise; longer parameters produce fewer signals with higher conviction. There is no magic combination that gives you the best of both worlds.

What changes in forex markets

Forex markets behave differently from equity indices in ways that matter for the Coppock Curve:

No structural upward bias. The S&P 500 trends upward over decades because the underlying economy grows. EUR/USD does not have that bias — it oscillates around a central tendency. This means the Coppock Curve on forex pairs spends more time oscillating around zero rather than spending prolonged periods in positive territory. Sell signals become as important as buy signals, unlike in equities where Coppock intentionally ignored the sell side.

Smoother bottoms. Equity markets form sharp V-bottoms during panics. Currency pairs tend to form rounder, more gradual turning points. The Coppock Curve was specifically designed for sharp bottoms — the grieving metaphor assumes a sudden loss followed by gradual recovery. On forex, the signal timing may be less precise because the turning points are less dramatic.

Lower volatility on major pairs. EUR/USD and USD/JPY have annualized volatility around 8-12%, compared to 15-20% for the S&P 500. The Coppock Curve readings on forex pairs will be proportionally smaller. Readings of +5 or -5 on daily EUR/USD are meaningful; the same readings on a monthly stock index would be insignificant. Do not apply the same absolute thresholds across different instruments.

Combining Coppock with trend filters on shorter timeframes

On daily forex charts, the Coppock Curve works best as a confirmation tool rather than a standalone signal generator. A practical setup:

1. Determine the trend direction using a 50-period or 200-period SMA on the daily chart
2. Only take Coppock buy signals (upward turns from negative territory) when price is above the SMA
3. Only take Coppock sell signals (downward turns from positive territory) when price is below the SMA

This trend filter eliminates the counter-trend signals that account for most of the false signals on shorter timeframes. You miss some genuine reversals, but you avoid the far more common scenario of buying a small bounce in a larger downtrend.

Intraday: does it work on H1 or H4?

Technically, you can apply the Coppock Curve to any timeframe. On H4 with compressed parameters like ROC 10, ROC 7, WMA 5, the indicator produces tradeable signals on major forex pairs. Below H4, the indicator starts generating too much noise relative to its signal value. The WMA smoothing that works beautifully on monthly data becomes insufficient on M15 or M5, where price movements are dominated by spread fluctuations and order flow dynamics that have nothing to do with the kind of long-cycle momentum the indicator was designed to measure.

The honest assessment: the further you move from the Coppock Curve's original monthly-chart-on-equity-indices design, the more you are using a tool outside its intended purpose. It can still add value as a confirmation filter on daily and weekly forex charts, but expecting it to perform at the same level as it does on monthly S&P 500 data is setting yourself up for disappointment.

Theories are nice. Track records are better. The Coppock Curve has over 60 years of real-world data on the S&P 500 and Dow Jones Industrial Average, which makes it one of the most extensively tested momentum indicators in existence. Let's look at what the numbers actually show.

Signal frequency and returns on the Dow (1950-present)

Using monthly data on the Dow Jones Industrial Average since 1950, the Coppock Curve has generated approximately 15 buy signals — roughly one every five years. The average six-month return following a buy signal was 6.5%, with 80% of those returns being positive. Compare that to the average six-month return at any random point, which is significantly lower, and you can see the indicator is doing something beyond random chance.

On the sell side (using the unofficial downward-cross signal), the six-month return after sell signals averaged just 0.5%, with fewer than half of the returns positive. The indicator may not have been designed for sell signals, but the sell-side data is telling: when the Coppock Curve says momentum has shifted negative, the market tends to underperform.

Major buy signals that worked

The 2009 recovery is the textbook example. The Coppock Curve on the monthly S&P 500 chart plunged deep into negative territory during 2008, reaching extreme readings below -25. In early 2009, the curve began turning upward — the direction-change signal fired almost exactly at the March 2009 bottom. The zero-line cross confirmed later that year. Investors who acted on the direction change captured the beginning of an 11-year bull market. Those who waited for the zero-line cross still caught the vast majority of the move.

The COVID-19 crash in 2020 produced another clean signal. The curve dropped sharply into negative territory as markets fell over 30% in weeks. But the rebound was swift — fiscal and monetary stimulus stabilized prices quickly — and the Coppock Curve began recovering within months. The rapid V-shaped recovery was exactly the type of pattern the indicator was designed for: sharp decline, emotional capitulation, then a decisive shift in momentum.

Going further back, the indicator signaled buy opportunities in late 2002 (after the dot-com crash completed), in 1982 (ahead of the massive bull run of the 1980s), and in 1974 (after the brutal 1973-74 bear market). Each of these signals preceded multi-year rallies.

The sell signals that saved portfolios

The February 2001 sell signal occurred as the Coppock Curve crossed below zero on the monthly S&P 500 chart. Investors who exited at that point avoided most of the dot-com bear market, which eventually took the index down roughly 49% from its peak. The timing was not perfect — the index had already declined about 15% by February 2001 — but avoiding the remaining 35% of the drawdown more than justified the late exit.

The June 2008 sell signal was similarly well-timed. The curve crossed below zero several months before the Lehman Brothers collapse in September 2008. Investors who moved to cash on that signal sidestepped the panic selling that took the S&P 500 down another 40% in the following months.

Where it stumbled

The indicator is not infallible. During the 1990s bull market, the Coppock Curve generated a brief sell signal in 1998 related to the Asian financial crisis and the Long-Term Capital Management blowup. Investors who sold at that point missed several more years of strong gains before the eventual dot-com peak. The market correction was real, but it proved temporary — the kind of mid-cycle dip that the indicator's monthly timeframe occasionally misidentifies as a trend change.

More broadly, the Coppock Curve struggles in environments with shallow, frequent corrections. If the market declines 10-12% and recovers quickly (which has happened multiple times in recent years), the curve may barely dip below zero before bouncing back. These minor dips produce low-conviction signals because the "mourning period" never really gets going — there is no genuine capitulation to recover from.

Backtested risk-adjusted performance

Quantitative backtests consistently show that the Coppock Curve strategy delivers risk-adjusted returns that exceed buy-and-hold, even though the raw total return may be lower in some periods (because you are sitting in cash during parts of bull markets). The key advantage is drawdown reduction. By exiting when the curve crosses below zero and re-entering when it turns upward from negative territory, the strategy avoids the worst bear market drawdowns that can take years to recover from.

One backtested study on the S&P 500 showed a tuned Coppock strategy outperforming SPY by 51% when optimized with a four-bar confirmation filter (requiring four consecutive readings below zero before acting on a subsequent upward cross). The untuned version still outperformed modestly, suggesting the base indicator has genuine predictive value rather than being purely an artifact of optimization.

Applied beyond traditional indices

Mike Scott's research using a weekly Coppock Curve alongside Investor's Business Daily market direction calls found that the combination correctly identified successful rallies 79% of the time in bull markets and 45% of the time in bear markets. When applied to individual stock picks in early 2023, the average return was 25% with an 81% success rate — impressive numbers that suggest the indicator's momentum logic extends beyond just broad indices.

The honest bottom line

The Coppock Curve is not a magic bullet. It generates few signals, it lags by design, and it was never meant to catch exact bottoms or tops. But across six decades of data on major equity indices, it has demonstrated a consistent ability to keep investors on the right side of major trend changes. For long-term investors who can tolerate the patience required, its track record speaks for itself. For shorter-term traders, it serves as a valuable macro filter — a way to know whether the big-picture wind is at your back or in your face before you enter a position based on shorter-timeframe analysis.