Convergence between the US GAAP system and International Financial Reporting Standards could take three to five years, said Robert Herz, chairman of the Financial Accounting Standards Board (FASB).

The process of aligning US and international accounting rules will be ‘sustainable for the next three to five years’, but a decision on full adoption should be made after that point, he told Reuters.

Although many in the accounting profession have argued for a gradual process of convergence to continue until the two sets of standards match, Herz argued that this would be unsustainable and a final decision will have to be taken at some point.

“Most people seem to be arguing (for) continued convergence until the two sets of standards are identical. I think trying to get every nook and cranny, particularly all the nooks and crannies of US GAAP, could take quite a long period of time.”

He added that while the FASB is working with international lawmakers in London to continue convergence, any timetable would rely on receiving more public support: "I think the SEC needs to do a very thorough study from a public policy point of view of the impacts on our financial system and our economy. I am not clear that the public policy case has been made in this country yet for there to be an adoption type process."