順勢指標 (Commodity Channel Index，簡稱CCI)

順勢指標衡量了價格與移動平均線的相對位置。它可以用來顯示市場的超買超賣區域或者是對趨勢減弱發出信號。該指標理念與佈林帶類似，但它是通過指標線而不是超買超賣水平表現出來。

順勢指標是由Donald Lambert創造的，並在他的Commodities Channel Index: Tools for Trading Cyclic Trends 一書中有所描述。

交易信號

順勢指標最好和追蹤止損結合起來使用。

市場處於盤整期

• 如果CCI從下向上穿過-100，做多。
• 如果CCI自上而下穿過100，做空。

趨勢市場

背離是不多見的、很強的交易信號。它們多被用於中線交易。
• 看漲背離做多。
• 看跌背離做空。
 
示例：

IBM 公司股價與  14 日CCI ，根據交易信號進場，並在第二天設定跟蹤止損買入、賣出的掛單。

S1: 做空—順勢指標從超買區域下降。該筆交易在趨勢反彈的S2處止損。
S2: 做空—看跌背離。該筆交易在S3處的反彈止損。
S3: 做空—三重看跌背離。
L1: 做多—順勢指標從超賣區域上升。第二日收盤價低於該日，單子被掃損。2日後，追蹤止損的掛單成交。
S4: 做空—順勢指標從超買區域下降。
L2: 做多—順勢指標從超賣區域上升。
S5: 做空—順勢指標從超買區域下降，出現看跌背離。
L3: 做多—順勢指標從超賣區域上升，出現看漲背離。
?: 市場正處於趨勢中：價格超過前期高點。價格從超買區域下降時不要做多——等待看跌背離。
S6: 做空—看跌背離。
S7: 更強烈的交易信號—三重看跌背離。

設定

順勢指標的預設設定是20日週期，超買超賣水平為100/-100.

順勢指標的計算公式

順勢指標的計算公式十分的複雜。下面是20日CCI 的計算公式：
1. 計算中值:TP：

          (高點 + 低點 + 收盤價) / 3
2. TPMA：中值的20日平均值。
3. TP值減去TPMA
4. CCI計算方法：
• 過去20日內的TP值各自減去今日的TPMA值。
• 計算出20個結果的和，並除以20.
• 計算結果除以 0.015.

其他的時間週期（比如10日或30日）可以直接替代20日。

 
Commodity Channel Index
The Commodity Channel Index measures the position of price in relation to its moving average. This can be used to highlight when the market is overbought/oversold or to signal when a trend is weakening. The indicator is similar in concept to Bollinger Bands but is presented as an indicator line rather than as overbought/oversold levels.
The Commodity Channel Index was developed by Donald Lambert and is outlined in his book Commodities Channel Index: Tools for Trading Cyclic Trends.
Trading Signals
Commodity Channel Index is best used in conjunction with trailing buy- and sell-stops.
Ranging Market
• Go long if the CCI turns up from below -100.
• Go short if the CCI turns down from above 100.
Trending Market
Divergences are stronger signals that occur less frequently. They are mostly used to trade intermediatecycles.
• Go long on a bullish divergence.
• Go short on a bearish divergence.
 
EXAMPLE
IBM Corporation with   14 day Commodity Channel Index. The days shown are the signal days. Trades are entered using trailing buy- and sell-stops on the day following.
S1: Go short - Commodity Channel Index turns down above the overbought line. This trade is stopped out at the rally before S2.
S2: Go short - bearish divergence. This trade is stopped out during the rally before S3.
S3: Go short - bearish triple divergence.
L1: Go long - Commodity Channel Index turns up from below the oversold line. The next day closes below the low of the signal day, causing the trade to be stopped out. A trailing buy-stop would stop us back in two days later.
S4: Go short - Commodity Channel Index turns down above the overbought line.
L2: Go long - Commodity Channel Index turns up from below the oversold line.
S5: Go short - Commodity Channel Index turns down above the overbought line and bearish divergence occurs.
L3: Go long - Commodity Channel Index turns up from below the oversold line and bullish divergence occurs.
?: The market is now trending (evidenced by the break above the previous high).
Do not go short when Commodity Channel Index turns down above the overbought line - wait for a bearish divergence.
S6: Go short - bearish divergence.
S7: Even stronger signal - bearish triple divergence.
Setup
The default Commodity Channel Index is set at 20 days with Overbought/Oversold levels at 100/-100. To alter the default settings - Edit Indicator Settings.
See Indicator Panel for directions on how to set up an indicator.
Commodity Channel Index Formula
The Commodity Channel Index calculation is fairly complicated. Here is the formula for 20-day CCI:
1. Calculate Typical Price ("TP"):

          (High + Low + Close) / 3
2. Calculate TPMA: a 20-day simple MA of TP.
3. Subtract TPMA from TP
4. Divide the result by the following:
• Subtract today's TPMA from TP for each of the last 20 days.
• Sum the absolute values and divide by 20.
• Multiply the result by 0.015.
Any other time period (e.g. 10 days or 30 days) can be substituted for 20.

本文翻譯由兄弟財經提供

文章來源：http://www.incrediblecharts.com/indicators/commodity_channel_index.php