What is Beta?

Explanation of Beta

Beta is a key input in the Capital Asset Pricing Model (CAPM), where it is used to estimate the cost of equity. It measures systematic risk, meaning the portion of total risk that cannot be diversified away and is attributable to broader market movements.

A Beta of 1 indicates that the asset’s returns are expected to move in line with the market. A Beta greater than 1 suggests higher volatility relative to the market, while a Beta below 1 suggests lower relative volatility.

In practice, Beta is typically derived through regression analysis of historical share price returns against a market index. In UK corporate finance and valuation contexts, Beta is often adjusted to reflect a company’s capital structure, producing equity Beta and asset Beta figures for use in discounted cash flow modelling and transaction analysis.

Key characteristics of Beta

Key characteristics of Beta include:

• It measures systematic risk relative to a defined market benchmark.
• It forms a core component of the Capital Asset Pricing Model.
• It is typically estimated using historical return data and statistical regression.
• It can be adjusted to reflect differences in financial leverage.
• It is used in determining a company’s cost of equity in valuation models.

How Beta works

1. Historical returns for a company’s shares and a relevant market index are collected over a defined period.
2. Statistical regression analysis is performed to estimate the relationship between the two sets of returns.
3. The resulting coefficient represents the company’s Beta relative to that market.
4. The Beta is incorporated into the CAPM formula to estimate the cost of equity.

Example of Beta in practice

A UK listed engineering company is being valued using a discounted cash flow model. Its estimated equity Beta, based on regression against a UK market index, is 1.3. This figure is used within the CAPM to calculate the company’s cost of equity, which feeds into the weighted average cost of capital applied in the valuation.

Related terms

• Capital Asset Pricing Model (CAPM)
• Cost of equity
• Weighted average cost of capital (WACC)
• Systematic risk
• Asset Beta
• Equity Beta
• Discounted cash flow (DCF)

Questions about Beta

What does a Beta of 1 mean?

A Beta of 1 indicates that a company’s share price is expected to move in line with the relevant market index. If the market rises or falls by a given percentage, the share price is expected to change by a similar percentage.

Can Beta be negative?

Yes. A negative Beta indicates that the asset’s returns have historically moved in the opposite direction to the market. This is uncommon for operating companies but may arise in specific investment strategies or asset classes.

Why is Beta adjusted for capital structure?

Financial leverage affects the risk borne by equity holders. To compare companies consistently, analysts often remove the impact of debt to calculate asset Beta and then reapply an appropriate capital structure for modelling purposes.

Is Beta relevant for private companies?

Private companies do not have quoted share prices from which to derive a direct Beta. In valuation work, Beta is often estimated by reference to comparable listed companies and adjusted to reflect the private company’s capital structure.