If you own shares in Carpentaria Resources Limited (ASX:CAP) then it's worth thinking about how it contributes to the volatility of your portfolio, overall. In finance, Beta is a measure of volatility. Volatility is considered to be a measure of risk in modern finance theory. Investors may think of volatility as falling into two main categories. The first category is company specific volatility. This can be dealt with by limiting your exposure to any particular stock. The other type, which cannot be diversified away, is the volatility of the entire market. Every stock in the market is exposed to this volatility, which is linked to the fact that stocks prices are correlated in an efficient market.

Some stocks mimic the volatility of the market quite closely, while others demonstrate muted, exagerrated or uncorrelated price movements. Beta is a widely used metric to measure a stock's exposure to market risk (volatility). Before we go on, it's worth noting that Warren Buffett pointed out in his 2014 letter to shareholders that 'volatility is far from synonymous with risk.' Having said that, beta can still be rather useful. The first thing to understand about beta is that the beta of the overall market is one. A stock with a beta greater than one is more sensitive to broader market movements than a stock with a beta of less than one.

View our latest analysis for Carpentaria Resources

What we can learn from CAP's beta value

Looking at the last five years, Carpentaria Resources has a beta of 0.85. The fact that this is well below 1 indicates that its share price movements haven't historically been very sensitive to overall market volatility. This means that -- if history is a guide -- buying the stock would reduce the impact of overall market volatility in many portfolios (depending on the beta of the portfolio, of course). Beta is worth considering, but it's also important to consider whether Carpentaria Resources is growing earnings and revenue. You can take a look for yourself, below.

How does CAP's size impact its beta?

Carpentaria Resources is a rather small company. It has a market capitalisation of AU$8.8m, which means it is probably under the radar of most investors. Companies with market capitalisations around this size often show poor correlation with the broader market because market volatility is overshadowed by company specific events, or other factors. It's worth checking to see how often shares are traded, because very small companies with very low beta values are often only thinly traded.