What Is a Momentum Indicator? Definition and Common Indicators

What Are Momentum Indicators?

Momentrum indicators are technical analysis tools used to determine the strength or weakness of a stock's price. Momentum measures the rate of the rise or fall of stock prices. Common momentum indicators include the relative strength index (RSI) and moving average convergence divergence (MACD).

Understanding Momentum Indicators

Momentum measures the rate of the rise or fall in stock prices. From the standpoint of trending, momentum is a very useful indicator of strength or weakness in the issue's price. History has shown us that momentum is far more useful during rising markets than during falling markets; the fact that markets rise more often than they fall is the reason for this. In other words, bull markets tend to last longer than bear markets.

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RSI

The relative strength index was created by J. Welles Wilder Jr. in the late 1970s; his "New Concepts in Trading Systems" (1978) is now an investment-lit classic. On a chart, RSI assigns stocks a value between 0 and 100. Once these numbers are charted, analysts compare them against other factors, such as the undersold or underbought values. To reach the best evaluation, experts generally chart the RSI on a daily time frame rather than hourly. However, sometimes shorter hourly periods are charted to indicate whether it is a good idea to make a short-term asset purchase.

There has always been a little confusion over the difference between relative strength, which measures two separate and different entities by means of a ratio line, and the RSI, which indicates to the trader whether or not an issue's price action is created by those over-buying or over-selling it. The well-known formula for the relative strength index is as follows:

﻿ \begin{aligned} &\textbf{RSI} = 100 - \left(\frac{100}{1 + RS}\right)\\ &\textbf{RS} = \frac{\text{Average of x days' up closes}}{\text{Average of x days' down closes}}\\ &\textbf{where:}\\ &RSI= \text{relative strength index} \end{aligned}﻿

At the bottom of the RSI chart, settings of 70 and 30 are considered standards that serve as clear warnings of, respectively, overbought and oversold assets. A trader with today's simple-to-use software may choose to reset the indicators' parameters to 80 and 20. This helps the trader to be sure when making the decision to buy or sell an issue and not pull the trigger too fast.

Ultimately, RSI is a tool to determine low-probability and high-reward setups. It works best when compared to short-term moving-average crossovers. Using a 10-day moving average with a 25-day moving average, you may find that the crossovers indicating a shift in direction will occur very closely to the times when the RSI is either in the 20/30 or 70/80 range, the times when it is showing either distinct overbought or oversold readings. Simply put, the RSI forecasts sooner than almost anything else an upcoming reversal of a trend, either up or down.

A Demonstration

It is important to recognize that many traders view the RSI value of 50 to be a support and resistance benchmark. If an issue has a difficult time breaking through the 50-value level, the resistance may be too high at that particular time, and the price action may fall off again until there is enough volume to break through and continue on to new levels. An issue falling in price may find support at the 50 value and bounce off this level again to continue an upward rise in price action.

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