#现货与合约策略 RSI (Relative Strength Index) is a technical analysis tool that measures the strength of buying and selling forces in the market by calculating the ratio of upward to downward momentum over a certain period.
1. Core Principle
By comparing the proportion of price increases to total volatility over a specific period, we can determine whether the market is overbought or oversold. The value ranges from 0 to 100, essentially being a percentage indicator.
2. Calculation Steps (taking 6 days as an example)
1. Determine the period and price differences:
Calculate the difference in closing prices for each day over 6 days compared to the previous day's closing price (upward is recorded as a positive number, downward as a negative number).
Example: 6-day price differences are: +2, +3, -1, +1, -2, +4
2. Distinguish between upward and downward movements:
- Upward movement: take the absolute values of all positive differences, which are 2, 3, 1, 4, ignoring the negatives.
- Downward movement: take the absolute values of all negative differences, which are 1, 2, ignoring the positives.
3. Calculate the average upward and downward movements:
Average upward movement (AU) = Sum of upward movements ÷ Number of periods (6 days)
Example: (2+3+1+4) ÷ 6 = 10 ÷ 6 ≈ 1.67
Average downward movement (AD) = Sum of downward movements ÷ Number of periods (6 days)
Example: (1+2) ÷ 6 = 3 ÷ 6 = 0.5
4. Calculate the Relative Strength (RS)
RS = Average upward movement ÷ Average downward movement
Example: RS = 1.67 ÷ 0.5 = 3.34
5. Convert to RSI indicator:
- RSI = 100 - [100 ÷ (1 + RS)]
Example: RSI = 100 - [100 ÷ (1 + 3.34)] ≈ 100 - 23.04 = 76.96
3. Key Logic
If the upward price momentum is strong (AU much greater than AD), RSI approaches 100, indicating "overbought" (buying pressure is excessively consumed, potential for a drop).
If the downward price momentum is strong (AD much greater than AU), RSI approaches 0, indicating "oversold" (selling pressure is excessively consumed, potential for a rebound).
4. Common Periods and Application Scenarios
Short-term trading: commonly uses 6-day or 9-day periods, RSI > 70 is considered overbought, < 30 is considered oversold.
Medium-term trend: commonly uses a 14-day period, combined with trend lines or price patterns to judge direction.
Divergence signals: when price reaches new highs/lows but RSI does not synchronize, it may indicate a trend reversal (e.g., top divergence, bottom divergence).
5. Notes
More effective in a sideways market: In a clearly trending market (e.g., one-sided upward), RSI may remain in the overbought zone for a long time without reversing;
Must be combined with other indicators: Using RSI alone may lead to misjudgments, it is recommended to combine with candlestick patterns, trading volume, and other analyses.
