Mark-to-market (MTM or M2M) or fair value accounting refers to accounting for the "fair value" of an asset or liability based on the current market price, or the price for similar assets and liabilities, or based on another objectively assessed "fair" value. Fair value accounting has been a part of Generally Accepted Accounting Principles (GAAP) in the United States since the early 1990s, and is now regarded as the "gold standard" in some circles. Failure to use it is viewed as the cause of the Orange County Bankruptcy, even though its use is considered to be one of the reasons for the Enron scandal and the eventual bankruptcy of the company, as well as the closure of the accounting firm Arthur Andersen.