"If the plan was between 80% and 90% funded for 2012, additional funding could be due as early as March 31, 2013 for calendar year plans.... If the plan was over 90% funded for 2012, additional funding may be due by September 15, 2013, for calendar year plans. If benefit restrictions are not a concern for your plan, the minimum funding rules allow you to put off the increased funding requirements until 2014."  MORE >>