RSI Demystified

Here I am... as promised. After the last post and the reference to RSI, it is but natural that I talk about RSI today. It was a close call as I also wanted to discuss few individual stocks which are getting interesting but then those have to wait for another time.

Some basics before we start; In technical analysis we have indicators and oscillators. Indicators are calculated based on the price, volume, momentum, volatility, etc. They give us additional information about the price and help us in technical analysis. Indicators which vary only in a range are called oscillators and Relative Strength Index (RSI) is one of them. It tells us about the strength or weakness in the trend of the security being analysed. It is calculated as;

RSI = 100 - 100 / (1 + RS)

Where RS = Average of x days' up closes / Average of x days' down closes

Usually RSI is calculated for a period of 14 days and it is the most popular duration. So for 14 days; RS = (Sum of Gains over last 14 days/14) / (Sum of Losses over last 14 days/14)

The formula above makes sure that RSI varies between 0 and 100. However, RSI does not practically go to 0 or 100 very often. We have seen RSI in many charts so I do not need to post one to explain more.

Most important use of RSI is to confirm the trend. If you think that the security is in an uptrend, be sure to confirm that RSI is above 50. Similarly RSI below 50 acts to help us confirm the downtrend for the security. However, main question is how do we use RSI for trading? There are various ways of doing so... some of them are;

• Overbought / Oversold conditions
• Divergences
• Positive / Negative Reversals
• Failure Swings
• Trending IDs

What we generally use is the first two. Rest of them do not occur often and are not so easy to spot. Overbought condition was already (more or less) explained in last post. Only thing to add here is it is universally accepted that RSI above 70 is overbought condition and below 30 is oversold condition.

Next, Divergence is used to identify the impending reversal in the trend of the security being analyzed. It usually happens when security makes a higher high (or higher low) but RSI fails to follow through. This is called as Bearish (negative) divergence - First rectangle in the chart below. Vice versa situation where security seems bearish but RSI is going up gives Bullish (positive) divergence and it usually signals things are about to turn positive.

My apologies for not coming up with a better graph which will give a clearer picture but I believe this one will also give the basic idea. Will not be talking about the balance 3 ways to trade RSI but will surely visit them if situation calls for.

I am happy that I was able to follow up yesterday's come back post with this small tutorial kind of post and hope that you will enjoy reading it as much as I enjoyed writing it. RSI is probably one of the most popular oscillator and it will continue to be part of our future discourse so this surely is just the beginning of it. Will think about the third post tomorrow and decide whether to write another tutorial or post some stocks specific charts. If you have any ideas, I am all ears.

 Stay tuned for my (probably) first hat-trick tomorrow. Happy Trading.