The new requirements take effect in July 2009, although entities are permitted to adopt them earlier.

The project was undertaken jointly with the Financial Accounting Standards Board. The objective was to develop a single accounting standard that would ensure that the accounting for business combinations is the same whether an entity is applying international standards (IFRS) or U.S. standards (GAAP).

Over the past decade the average annual value of corporate acquisitions worldwide has been the equivalent of 8 percent to 10 percent of the total market capitalization of listed securities, said IASB.

In publishing its equivalents to IFRS 3 and IAS 27, the FASB has made fundamental changes to its accounting for business combinations, most of which bring U.S. accounting into line with the existing IFRS 3 and IAS 27. Other revisions will change both IFRSs and U.S. GAAP. The revised IFRS 3 reinforces the existing IFRS 3 model but remedies problems that have emerged in its application.

"Now the accounting requirements in IFRSs and U.S. GAAP will be substantially the same, thanks largely to the changes that the FASB has made to U.S. GAAP," said IASB Chairman Sir David Tweedie. "The changes to IFRSs have, in contrast, been relatively small."