Debt is used to finance and pay for undertakings and business around the world. Debt levels are worth 3 years of GDP in many countries that have an annual GDP/person above $10,000. Global debt levels are perhaps worth two or three years of GDP. GDP (at currency exchange rate) was $40 trillion during 2004. Debt levels may therefore be about $100 trillion.

$5.7 trillion of debt was issued in 2004 according to Thomson Financial numbers, while GDP grew $4 trillion (currency exchange rate). That does not mean that debt grew faster than GDP on a global average (even if it has done so for years after 2001 in the USA). Debt is often issued with a repayment plan (a "time to maturity" in some cases), repayment times may be between a few days (interbank cash flow management) and 50 years or longer (consumer real estate debt). The average repayment time of all global outstanding debt is perhaps 10 years.

When debt matures new debt is many times issued to repay the old debt, perhaps from the same creditor. That is one reason why debt issuance far surpasses equity issuance in currency value. Equity is another way of financing business, as it has no set time to maturity and pays no set interest. It pays profit from the company it is a claim on.