Badly underfunded pension accounts at some of the nation’s largest corporations are testing the might of federal coffers to cover shortfalls. But the problem is also raising hard questions about the current body of pension rules, and is prompting a growing call for pension reform.

While experts and public policy makers seem resigned to the inevitability of pension reform, the look and feel of new pension rules as they will apply to corporations offering the plans remains to be seen. Observers say new rules likely will include some combination of provisions intended to assure companies adequately fund their plans and have less opportunity to default on their pension obligations.