One way to measure GDP is to use the income approach, which sums corporate profits, employee compensation, and taxes on production and imports. When the U.S. Bureau of Economic Analysis (BEA) measures GDP using this approach, it relies on annual tabulations of corporate income tax returns prepared by the Internal Revenue Service (IRS) as the primary source of information on corporate profits. An alternative way to measure corporate profits is to use accounting earnings data prepared according to Generally Accepted Accounting Principles (GAAP) and aggregate the data across listed firms. Although accounting earnings are different from taxable income and do not include profits from privately-held corporations, aggregate accounting earnings are an ex ante appealing proxy for corporate profits for at least two reasons.