rating

Ratings have huge influence on the price and demand for certain securities, particularly bonds: The lower the rating, the riskier the investment and the less the investment is worth. Low ratings often lead to less trading activity and thus liquidity problems. This is why downgrades (or rumors of downgrades) in an issuer's credit rating can have a significant impact on its securities and on the market or industry.

Bonds are not the only securities affected by credit ratings, however. Preferred stock prices can move sharply when the issuer's credit rating changes (as this is an indicator of the issuer's ability to meet preferred dividend obligations). Securities that are convertible into a company's debt are also affected by credit ratings, especially if the convertible security is trading near or above the point at which the holder may convert the security to debt.

Low ratings are not always bad. They simply mean there is more risk associated with an investment and thus more potential for higher returns. In fact, many income investors actively enhance their returns by dividing securities into sectors based on certain characteristics such as credit rating, yield, coupon, maturity, etc., and then finding those sectors that will perform most favorably for the investor under certain market conditions.

Grouping securities by rating is common because investors are trying to rank investments, buy those positioned to improve and sell those expected to decline. An issuer doesn't need to actually default or lose money for an investor to lose money, however -- remember that the simple threat of default or decline can lower the price of the security. This threat could be sensitivity to adverse business conditions, rumors of a ratings downgrade or inaccuracy of ratings agency opinions.