Constant dollars

Inflation accounting is a term describing a range of accounting models designed to correct problems arising from historical cost accounting in the presence of high inflation and hyperinflation. Inflation accounting is used in countries experiencing high inflation or hyperinflation. For example, in countries experiencing hyperinflation the International Accounting Standards Board requires corporations to implement financial capital maintenance in units of constant purchasing power in terms of the monthly published Consumer Price Index. This does not result in capital maintenance in units of constant purchasing power since that can only be achieved in terms of a daily index.

Fair value accounting (also called replacement cost accounting or current cost accounting) was widely used in the 19th and early 20th centuries, but historical cost accounting became more widespread after values overstated during the 1920s were reversed during the Great Depression of the 1930s. Most principles of historical cost accounting were developed after the Wall Street Crash of 1929, including the presumption of a stable currency.

Under a historical cost-based system of accounting, inflation leads to two basic problems. First, many of the historical numbers appearing on financial statements are not economically relevant because prices have changed since they were incurred. Second, since the numbers on financial statements represent dollars expended at different points of time and, in turn, embody different amounts of purchasing power, they are simply not additive. Hence, adding cash of $10,000 held on December 31, 2002, with $10,000 representing the cost of land acquired in 1955 (when the price level was significantly lower) is a dubious operation because of the significantly different amount of purchasing power represented by the two numbers.

By adding dollar amounts that represent different amounts of purchasing power, the resulting sum is misleading, as one would be adding 10,000 dollars to 10,000 Euros to get a total of 20,000. Likewise subtracting dollar amounts that represent different amounts of purchasing power may result in an apparent capital gain which is actually a capital loss. If a building purchased in 1970 for $20,000 is sold in 2006 for $200,000 when its replacement cost is $300,000, the apparent gain of $180,000 is illusory.

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