What is RSI?

The Relative Strength Index (RSI) is a momentum indicator used in technical analysis to evaluate the speed and magnitude of recent price changes, helping to identify overbought or oversold conditions in a security's price. Here's a detailed explanation:

1. **Definition and Purpose**:
- The RSI is designed to measure the strength of a security's price movements, comparing gains to losses over a specified period.
- It is intended to help traders determine when a security is overbought (prices high relative to recent gains) or oversold (prices low relative to recent losses).
2. **Calculation and Interpretation**:
- The RSI calculation involves comparing the average upward price change (AvgU) to the average downward price change (AvgD) over a given period.
- The formula: RSI = 100 - [100 / (1 + (AvgU / AvgD))] transforms these averages into a percentage, with 70 indicating overbought conditions and below 30 indicating oversold conditions.
3. **Usage and Limitations**:
- RSI is most effective in identifying overbought and oversold conditions in ranging markets, where prices fluctuate within a defined range.
- It can also signal potential trend reversals or corrective moves in price.
- However, during strong trending markets, RSI may remain in overbought or oversold conditions for extended periods, making it less reliable.
4. **Practical Considerations**:
- Traders often look for divergences between RSI and price movements to anticipate potential reversals.
- RSI readings above 70 or below 30 are considered extreme, indicating potential reversals towards the average reading of 50.
- The RSI can be adjusted for specific securities to better fit their overbought and oversold levels, if necessary.

In summary, the RSI is a valuable tool for traders and analysts looking to understand the momentum and potential overbought or oversold conditions in a security's price. While it is most effective in ranging markets, it can also provide insights into potential price movements in trending markets.