# Coppock Curve

A Momentum & Oscillators concept (Rate-of-change cluster) in the LuxAlgo Library, with 1 indicator implementation.

## What is the Coppock Curve?

The Coppock Curve is a long-horizon momentum gauge built from smoothed rate of change. The classic construction, published by economist Edwin Coppock in Barron's in 1962, adds a 14-month and an 11-month [ROC](https://www.luxalgo.com/library/concept/roc/) of a stock index and smooths the sum with a 10-month [weighted moving average](https://www.luxalgo.com/library/concept/wma/). Its design brief was narrow: flag major bear-market bottoms on monthly charts. The often-repeated origin story is that Coppock chose the lookbacks after church advisers estimated that mourning lasts 11 to 14 months, reasoning that a bear market is processed like a bereavement.

The canonical signal is a single event: the curve turning upward from below the zero line, read as the start of a new long-term advance. Coppock offered no sell side. Later users added downturns from above zero as warnings, scaled the parameters down for weekly and daily charts, and applied the tool beyond equity indexes; those are extensions, and on fast timeframes the curve turns far more often and far less selectively than the monthly original.

The mechanics reward a second look. Below-zero readings mean the index sits lower than it did 11 and 14 months earlier, so the curve only hunts where a real bear market has already done damage; the front-weighted average then lets the most recent months steer the hook, which is what gives the signal its shape: [momentum](https://www.luxalgo.com/library/concept/momentum/) still deeply negative, but improving. Practitioners citing its record point to upward hooks near the major postwar bottoms, with the 2009 hook the widely cited modern example; the honest counterweight is sample size, since signals arriving a handful of times per decade leave the statistics thin by construction.

Modern usage dresses the classic in standard oscillator clothing: platform builds add a moving average of the curve for mechanical triggers, pivot and [divergence](https://www.luxalgo.com/library/concept/regular-bullish-bearish-divergence/) detection on faster variants, and freely adjustable lengths. The trade-off is one-directional: every step down in timeframe or lookback trades the original's rare, cycle-scale selectivity for ordinary smoothed-momentum behavior. Scaled to daily bars the Coppock Curve is a fine generic momentum composite, and nothing more; its distinct identity lives on the monthly chart it was designed for.

## How to identify the Coppock Curve signal

One construction, one canonical event: the below-zero upward hook on monthly closes.

1. Work from monthly closing prices of a broad index, the instrument class the tool was designed around.
2. Compute two rates of change, 14-month and 11-month, and add them.
3. Smooth the sum with a 10-month weighted moving average, front-weighted so recent months steer.
4. Wait for the setup: the curve below zero, meaning prices sit under their year-ago levels, the precondition of a bear market already priced.
5. The signal is the hook: the curve turning upward from below zero on a completed monthly bar, with intramonth hooks treated as provisional until the close.

## How it's calculated

A long-term momentum oscillator: a weighted moving average of the sum of two rates of change, designed for monthly index closes.

```
ROC_n(t) = 100 × (C_t - C_{t-n}) / C_{t-n}
Coppock_t = WMA_w(ROC_14 + ROC_11)_t
WMA_w(X)_t = (Σ (w - i) × X_{t-i} over i = 0..w-1) / (Σ (w - i) over i = 0..w-1)

  Coppock_t: Coppock Curve value at period t
  C_t: close of period t (monthly in the original definition)
  ROC_n(t): n-period rate of change in percent
  n: ROC lookback (defaults 14 and 11)
  WMA_w(X)_t: linearly weighted moving average of series X with length w
  X: series being averaged, here ROC_14 + ROC_11
  w: WMA length (default 10)
  i: offset within the WMA window (weight w for the newest value down to 1 for the oldest)
  t: period index
```

Edwin Coppock published the indicator in 1962 for monthly Dow and S&P closes; the classic buy signal is an upturn from below zero.

Charting platforms apply the same 14, 11 and 10 defaults on any timeframe and source; added signal lines or different sources are later variations, not part of the original definition.

## How traders use it

- As a long-cycle bottom detector on monthly index charts: a decline below zero followed by an upward hook is the classic buy condition, usually evaluated on closed monthly bars so an intramonth hook cannot vanish before the signal is final.
- As a slow regime backdrop: above zero and rising supports risk-on positioning, below zero and falling says long-term momentum is negative, a role similar to a [higher-timeframe trend filter](https://www.luxalgo.com/library/concept/higher-timeframe-trend-filter/).
- Scaled to weekly or daily charts with shorter ROC and smoothing lengths, where it behaves like other smoothed momentum composites and is traded on zero-line crosses and divergences rather than rare cycle turns.
- With mechanical triggers added: a moving average of the curve itself converts the visual hook into a crossover event, tightening the definition at the cost of a little extra delay.
- As one voice in bottom-fishing confluence: allocators pair the monthly hook with breadth washouts and valuation context, using the curve to time scale-in schedules rather than as a lone all-in signal.

## Coppock Curve vs related momentum composites

- **Know Sure Thing** (https://www.luxalgo.com/library/concept/know-sure-thing/): Martin Pring's KST generalizes the same idea. Where the Coppock Curve sums two ROCs under one weighted smoothing and waits for one canonical signal, KST blends four smoothed ROCs with rising weights and trades signal-line and zero-line crosses in both directions.
- **ROC** (https://www.luxalgo.com/library/concept/roc/): ROC is the raw ingredient: a single lookback, no smoothing, read from zero crosses and extremes bar by bar. The Coppock Curve is a weighted, smoothed composite of two ROCs, deliberately slow so it turns only a handful of times per cycle on monthly data.
- **MACD** (https://www.luxalgo.com/library/concept/macd/): MACD measures momentum as the spread of two price averages and serves swing timeframes with signals in both directions. The Coppock Curve is a single-purpose cycle tool: one buy-side event, monthly data, bear-market preconditions. Different clocks, different jobs.

## FAQ

### How is the Coppock Curve calculated?

Take a 14-period rate of change and an 11-period rate of change of closing prices, add them, then smooth the sum with a 10-period weighted moving average. The original applies this to monthly index closes; platform implementations keep the same structure and let you change the three lengths.

### Is the Coppock Curve only a buy signal?

As designed, yes: Coppock's signal was the curve hooking upward from below zero on a monthly chart, marking a candidate bear-market bottom. Downturns from above zero are a later, less standardized reading. Either way it is a slow gauge, and an early hook can still fail inside an ongoing bear market.

### Has the Coppock Curve actually worked historically?

Its advocates can point to upward hooks near most major US bear-market bottoms of the past several decades, with the 2009 signal the celebrated modern case; its critics point to hooks that fired early inside ongoing declines and to the tiny sample a once-per-cycle signal accumulates. Both are right. The honest reading is a tool with a respectable but statistically thin record, best used to time scaling rather than to declare bottoms.

### Is the mourning-period story about the settings true?

It is the origin story Coppock himself told: he asked church officials how long people grieve, was told 11 to 14 months, and used those spans as his rate-of-change lookbacks, treating a bear market as a bereavement the market must process. Whatever its psychology, the story encodes a defensible intuition, that major bottoms need roughly a year of washed-out comparisons, which is what the below-zero precondition enforces.

### Can the Coppock Curve be used for selling or shorting?

Not as designed; the method is deliberately asymmetric. Bottoms of the kind it hunts are compressed, washed-out events that momentum hooks catch tolerably well, while tops tend to be long distributions that a slow monthly composite rolls over far too late to trade. Users who want the sell side either read above-zero downturns as gradual de-risking cues or pair the curve with faster tools and accept that the edge, if any, lives on the buy side.

### What settings work for daily charts?

Common scalings keep the 14/11/10 proportions and reinterpret them as days or weeks, or double them for smoother behavior. The result is a serviceable smoothed-momentum oscillator, tradeable on zero-line crosses and divergences, but the translation discards what made the original distinctive: monthly bars and year-scale lookbacks are why its signals were rare and its preconditions meant something. Scaled down, it competes with every other momentum composite on equal, unremarkable terms.

## Implementations in the Library

- Coppock Curve (LuxAlgo, the standard build of the classic formula): https://www.luxalgo.com/library/indicator/coppock-curve/

## Related concepts

- Momentum: https://www.luxalgo.com/library/concept/momentum/
- Disparity Index: https://www.luxalgo.com/library/concept/disparity-index/
- ROC: https://www.luxalgo.com/library/concept/roc/
- ROC-of-ROC: https://www.luxalgo.com/library/concept/roc-of-roc/
- Chande Momentum Oscillator: https://www.luxalgo.com/library/concept/chande-momentum-oscillator/
- Know Sure Thing: https://www.luxalgo.com/library/concept/know-sure-thing/
- Detrended Price Oscillator: https://www.luxalgo.com/library/concept/detrended-price-oscillator/
- TRIX: https://www.luxalgo.com/library/concept/trix/
- Psychological Line: https://www.luxalgo.com/library/concept/psychological-line/
- Special K: https://www.luxalgo.com/library/concept/special-k/

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Source: https://www.luxalgo.com/library/concept/coppock-curve/ (LuxAlgo Library, the encyclopedia of trading & technical analysis). Free to use with attribution: https://www.luxalgo.com/library/license/