There are significant differences in the ways U.S. generally accepted accounting principles, or GAAP, and the international financial reporting standards, or IFRS, treat income or expense items that are irregular. Investors should have a good understanding of these items and how they are reported.

How Unusual or Infrequent Items Are Treated

Some items occurring on income statements are reported separately from normal income because they are considered irregular and non-recurring. Special considerations are given to so-called unusual or infrequent items to provide clarity about special or rare circumstances to investors or regulators about a firm's current and/or future financial performance.

Examples of unusual or infrequent items include gains or losses from a lawsuit; losses or slowdown of operations due to natural disasters; restructuring costs; costs associated with acquiring another business; and plant shutdown costs. Some unusual items are also categorized as discontinued operations or an adjustment due to changing accounting methods.

Accounting Treatment Under U.S. GAAP

For GAAP, unusual or infrequent items appear on an income statement gross of any tax implications. These items are presented separately on the income statement.

GAAP rules were changed in January 2015, and the concept of extraordinary items was eliminated in an effort to reduce the cost and complexity of preparing financial statements. It is still necessary for companies to disclose infrequent and unusual events (such as losses from theft or early retirement of debt), but now without designating them as extraordinary.

Accounting Treatment Under IFRS

The IFRS does not hold special distinctions for items of operational nature that occur irregularly or infrequently; rather, all results are disclosed as revenues, finance costs, post-tax gains or losses, or results from associates and joint ventures.

The International Accounting Standards Board, or IASB, ceased recognizing extraordinary items under IFRS rules in 2002. The IFRS has a separate disclosure required for income or expenses of abnormal size or nature. These disclosures can be on the face of the income statement or in the notes.