Lendings to stable financial entities such as large companies or governments are often termed “risk free” or “low risk” and made at a so-called “risk-free interest rate”. This is because the debt and interest are highly unlikely to be defaulted. A good example of such risk-free interest is a US Treasury security - it yields the minimum return available in economics, but investors have the comfort of the sure expectation that the US Treasury will not default on its debt instruments. A risk-free rate is also commonly used in setting floating interest rates, which are usually calculated as the risk-free interest rate plus a bonus to the creditor based on the creditworthiness of the debtor (in other words, the risk of him defaulting and the creditor losing the debt).

However, if the real value of a currency changes during the term of the debt, the purchasing power of the money repaid may vary considerably from that which was expected at the commencement of the loan. So from a practical investment point of view, there is still considerable risk attached to “risk free” or “low risk” lendings. The real value of the money may have changed due to inflation, or, in the case of a foreign investment, due to exchange rate fluctuations.

The Bank for International Settlements is an organisation of central banks that sets rules to define how much capital banks have to hold against the loans they give out.

Specific bond debts owed by both governments and private corporations is rated by rating agencies, such as Moody’s, A.M. Best and Standard & Poor’s. The government or company itself will also be given its own separate rating. These agencies assess the ability of the debtor to honor his obligations and accordingly give him a credit rating. Moody’s uses the letters Aaa Aa A Baa Ba B Caa Ca C, where ratings Aa-Caa are qualified by numbers 1-3. Munich Re, for example, currently is rated Aa3 (as of 2004). S&P and other rating agencies have slightly different systems using capital letters and +/- qualifiers.

A change in ratings can strongly affect a company, since its cost of refinancing depends on its creditworthiness. Bonds below Baa/BBB (Moody’s/S&P) are considered junk- or high risk bonds. Their high risk of default (approximately 1.6% for Ba) is compensated by higher interest payments. Bad Debt is a loan that can not (partially or fully) be repaid by the debtor. The debtor is said to default on his debt. These types of debt are frequently repackaged and sold below face value. Buying junk bonds is seen as a risky but potentially profitable form of investment.