A stock has a beta value of 0.

Beta measures the sensitivity of a stock’s returns to movements in the market as a whole, based on historical co-movement with a chosen market index. A beta of 1 indicates the stock has tended to move in line with the market. A beta greater than 1 indicates higher sensitivity and therefore higher systematic risk, meaning the stock has tended to rise more than the market in up markets and fall more in down markets. A beta below 1 indicates lower sensitivity to market movements. With a beta of 0.85, the stock has historically moved about 85% as much as the market, so it is less volatile than the market in systematic risk terms. This does not mean it will outperform or underperform the benchmark, and it does not describe relative performance in percentage terms. Beta is not a performance measure, it is a risk measure. CISI exam traps often include statements that confuse beta with return or with tracking error. The correct interpretation is lower market-related volatility than the market overall.