During the mid-20th century, a variety of future traders established the concept of mark-to-market in an effort to better define the positions of financial securities and other instruments. This concept is fundamentally based on the accounting methods of the futures market.
When taking a position, the future traders deposit money with an exchange under the umbrella of a contract. This deposit is known as the margin and is intended to protect the exchange against a financial loss. When the trading day ends, the market value of the instrument is established. If the value has increased, the trader receives the profit from the exchange. However, if the market value decreases, the trader's deposit is charged. If the trader's account falls below the threshold of the contract, he or she must deposit more into the account. This is known as a margin call. The entire process uses the mark-to-market process and is a well-regulated way to determine the present value of an instrument.
During the 1980s, traders began to find ways to take advantage of the other parts of the market, specifically over-the-counter derivatives, which are formula-based contracts not traded on exchanges. This meant that the market price was not established by the active market and the value could not be adequately determined immediately. Most of these instruments were revalued on a quarterly or annual basis. This led to a large amount of fraud, especially in the case of interest rate swaps in which cash flow is exchanged for a stream of interest payments.