The problems of accounting for defined benefit pensions represents a significant issue on corporate balance sheets.  As of December 31, 2010, of the S&P 500 companies the funded ratio of plans was 81%, and corporate governance reports it the #1 concern in corporate planning.  One of the largest parts to the problem is understanding just how big the liabilities are, as older expectations and differing measurements make sets of circumstances difficult to compare.

Rules tending to earlier expensing and more conservative discounting result in even more unfavorable pension obligation reporting.  In reality, this is merely a move to reporting reliability.  For those companies in far past their means, this is potentially dire trouble.  For the unchecked problem of obligation underfunding, IFRS affects the problem by exploding it.

http://ifrslibraries.cloudaccess.net/component/content/article/34-ifrs/46-pensiontimebomb.html