Beta

(redirected from beta radiation)
Also found in: Dictionary, Thesaurus, Medical, Encyclopedia.

Beta

The measure of an asset's risk in relation to the market (for example, the S&P500) or to an alternative benchmark or factors. Roughly speaking, a security with a beta of 1.5, will have move, on average, 1.5 times the market return. [More precisely, that stock's excess return (over and above a short-term money market rate) is expected to move 1.5 times the market excess return).] According to asset pricing theory, beta represents the type of risk, systematic risk, that cannot be diversified away. When using beta, there are a number of issues that you need to be aware of: (1) betas may change through time; (2) betas may be different depending on the direction of the market (i.e. betas may be greater for down moves in the market rather than up moves); (3) the estimated beta will be biased if the security does not frequently trade; (4) the beta is not necessarily a complete measure of risk (you may need multiple betas). Also, note that the beta is a measure of co-movement, not volatility. It is possible for a security to have a zero beta and higher volatility than the market.

Beta

A measure of a security's or portfolio's volatility. A beta of 1 means that the security or portfolio is neither more nor less volatile or risky than the wider market. A beta of more than 1 indicates greater volatility and a beta of less than 1 indicates less. Beta is an important component of the Capital Asset Pricing Model, which attempts to use volatility and risk to estimate expected returns.

beta

A mathematical measure of the sensitivity of rates of return on a portfolio or a given stock compared with rates of return on the market as a whole. A high beta (greater than 1.0) indicates moderate or high price volatility. A beta of 1.5 forecasts a 1.5% change in the return on an asset for every 1% change in the return on the market. High-beta stocks are best to own in a strong bull market but are worst to own in a bear market. See also alpha, capital-asset pricing model, characteristic line, portfolio beta.

Beta.

Beta is a measure of an investment's relative volatility. The higher the beta, the more sharply the value of the investment can be expected to fluctuate in relation to a market index.

For example, Standard & Poor's 500 Index (S&P 500) has a beta coefficient (or base) of 1. That means if the S&P 500 moves 2% in either direction, a stock with a beta of 1 would also move 2%.

Under the same market conditions, however, a stock with a beta of 1.5 would move 3% (2% increase x 1.5 beta = 0.03, or 3%). But a stock with a beta lower than 1 would be expected to be more stable in price and move less. Betas as low as 0.5 and as high as 4 are fairly common, depending on the sector and size of the company.

However, in recent years, there has been a lively debate about the validity of assigning and using a beta value as an accurate predictor of stock performance.

References in periodicals archive ?
Whether adjunctive beta radiation is an effective alternative is unclear from this dataset, but the results suggest that further investigation is needed.
It occurred by 8 months in 27% of patients randomized to placebo and 17% who received beta radiation.
Table 2 shows the beta radiation for the equivalent dose (Q) and supralinearity factor (I) for each sample studied.
Phosporous-32 poses no external radiation hazards, and its limited range prevents beta radiation from reaching the bone or underlying blood vessels, thus sparing the bone and bone marrow.
Strong Clinical Support for IVUS and Beta Radiation
Tenders are invited for dual chanel compact alfa and beta radiation counter
Tenders are invited for Supply/installation of Portable radiation Survey Meter with Photomultiplier Tube Detector for Gamma Radiation and Pancake type GM probe for beta Radiation.
Construction supply contamination meters with probes of different surfaces for beta radiation and / or alpha and accessories.
The subject of the tender is the supply of the following laboratory equipment: dual optical tweezers with fluorescence imaging, Differential Scanning Calorimeter, measuring instrument thermal stability of proteins and apparatus for measuring fluorescence, chemiluminescence and beta radiation in plates and gels.
SIR-Spheres[R] microspheres are radioactive polymer spheres that emit beta radiation.
Yttrium-90 emits only beta radiation, so that hospitalization or patient isolation for several days or even weeks after treatment is not required with Zevalin radioimmunotherapy.
For alpha and beta radiation, all monitored median values were consistent with median values for a reference air monitor placed away from the site in St.