Beta
A measure of systematic, or market risk — the portion of a portfolio or security's risk that is attributable to general market movements rather than company-specific or manager-specific factors.
A beta of 1.0 means the investment moves in line with the market. A beta above 1.0 indicates amplified market sensitivity; below 1.0 indicates lower sensitivity. Beta cannot be diversified away within a portfolio — it is the irreducible market exposure component.
Formula: Beta = Covariance(Security, Market) / Variance(Market)
For institutional allocators, understanding beta decomposition is critical for risk budgeting — ensuring the portfolio's aggregate market exposure is intentional and sized appropriately given the institution's risk tolerance and liability profile.
Frequently Asked Questions
What is beta in investing?
Beta measures systematic market risk — how much a portfolio or security moves relative to the overall market. A beta of 1.0 means it moves in line with the market; above 1.0 means more volatile; below 1.0 means less volatile.
How is beta calculated?
Beta = Covariance(Security, Market) / Variance(Market). It measures the sensitivity of an investment's returns to movements in a market benchmark.
Why does beta matter for portfolio construction?
Understanding beta is critical for risk budgeting. It ensures the portfolio's aggregate market exposure is intentional and appropriately sized for the institution's risk tolerance and liability profile.
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