The final rule addressed this issue by calculating SFA using separate investment return assumptions for SFA and non-SFA assets. For SFA assets, the assumption is 67 basis points plus the average of the three segment rates (approximately 4.85% today) for the month in which the average...
says PBGC made it clear that the rate plans will need to use is the lesser of the third segment rate plus 2.5 basis points (bps), which is roughly 5.5%, or the interest rate the plan used in its Form 5500 filing with the Department of Labor (DOL). ...