In accounting, mark to market is the act of assigning a value to a position held in a financial instrument based on the current market price for the instrument or similar instruments. For example, the final value of a futures contract that expires in 9 months will not be known until it expires. If it is marked to market, for accounting purposes it is assigned the value that it would fetch in the open market currently.
History and development
According to Stan Ross, CPA, the practice of mark to market as an accounting device first developed among traders on futures exchanges in the 19th century. It was not until the 1980s that the practice spread to big banks and corporations far from the traditional exchange trading pits, and beginning in the 1990s, mark-to-market accounting began to give rise to scandals.
To understand the original practice, consider that a futures trader, when taking a position, deposits money with the exchange, called a "margin". This is intended to protect the exchange against loss. At the end of every trading day, the contract is marked to its present market value. If the trader is on the winning side of a deal, his contract has increased in value that day, and the exchange pays this profit into his account. On the other hand, if he is on the losing side, the exchange will remove the appropriate amount from his account. If he cannot pay, then the margin is used as the collateral from which the loss is paid. As an example, the Chicago Mercantile Exchange, taking the process one step further, marks positions to market twice a day, at 10:00 am and 2:00 pm.[1]
Over-the-counter (OTC) derivatives on the other hand are not traded on exchanges, so their market prices are not as readily available. During their early development, OTC derivatives such as interest rate swaps were not marked to market frequently. Deals were monitored on a quarterly or annual basis, when gains or losses would be acknowledged or payments exchanged.
As the practice of marking to market caught on in corporations and banks, some of them seem to have discovered that this was a tempting way to commit accounting fraud, especially when the market price could not be objectively determined (because there was no real day-to-day market available), so assets were being 'marked to model' using estimated valuations derived from financial modeling, and sometimes marked to spurious valuations. See Enron and the Enron scandal.
Internal Revenue Code Section 475 contains the mark to market accounting method rule. Section 475 provides that dealers that elect mark to market treatment shall recognize gain or loss as if the property were sold for its fair market value on the last business day of the year, and any gain or loss shall be taken into account in that year. The section also provides that dealers in commodities can elect mark to market treatment for any commodity (or their derivatives) which is actively traded (i.e., for which there is an established financial market that provides a reasonable basis to determine fair market value by disseminating price quotes from broker/dealers or actual prices from recent transactions).
Simple example
Example: If an investor owns 100 shares of a stock purchased for $40 per share, and that stock now trades at $60, the "mark-to-market" value of the shares is equal to (100 shares × $60), or $6,000, whereas the book value might (depending on the accounting principles used) only equal $4,000.
Similarly, if the stock falls to $30, the mark-to-market value is $3,000 and the investor has lost $1,000 of the original investment. If the stock was purchased on margin, this might trigger a margin call and the investor would have to come up with an amount sufficient to meet the margin requirements for his account.
Marking-to-Market a Derivatives Position
In marking-to-market a derivatives position, at the end of each trading day, each counterparty exchanges the change in the market value of their position in cash. If one of the counterparties defaults in this daily exchange, that counterparty's position is immediately closed by the exchange and the clearing house is substituted for the counterparty's position. Marking-to-market virtually eliminates credit risk, but it requires monitoring systems that usually only large institutions can afford.
See Risk Management by Crouhy, Galai, & Mark, 2001, page 445
Use by Brokers
Stock brokers allow their clients to access credit via margin accounts. These accounts allow clients to borrow funds to buy securities. Therefore, the amount of funds available is more than the value of cash (or equivalents). The credit is provided by charging a rate of interest, in a similar way as banks provides loans. Even though the value of securities (stocks or other financial instruments such as options) fluctuates in the market, the value of accounts is not calculated in real time. Marking-to-market is performed typically at the end of the trading day, and if the account value falls below a given threshold, (typically a predefined ratio by the broker), the broker issues a margin call that requires the client to deposit more funds or liquidate his account.
Emergency Economic Stabilization Act of 2008
Section 132 of the proposed Emergency Economic Stabilization Act of 2008, titled "Authority to Suspend Mark-to-Market Accounting" restates the Securities and Exchange Commission’s authority to suspend the application of FAS 157 if the SEC determines that it is in the public interest and protects investors.
Section 133 of the proposed Act, titled "Study on Mark-to-Market Accounting," requires the SEC, in consultation with the Federal Reserve Board and the Department of the Treasury, to conduct a study on mark-to-market accounting standards as provided in FAS 157, including its effects on balance sheets, impact on the quality of financial information, and other matters, and to report to Congress within 90 days on its findings.[4]
1. The act of recording the price or value of a security, portfolio or account to reflect its current market value rather than its book value.
2. In terms of mutual funds, a MTM is when the net asset value (NAV) of the fund is valued upon the most current market values.
1. This is done most often in futures accounts to make sure that margin requirements are being met. If the current market value causes the margin account to fall below its required level, the trader will be faced with a margin call.
2. Mutual funds are marked to market on a daily basis at the market close so that investors have an idea of the fund's NAV.

