"Defined benefit plan sponsors overpaid $700 million in [PBGC] premiums in the past six years by not following best practices ... The [study] analyzed public Form 5500s and the PBGC's historical premium database for 23,000 single-employer plans, with a focus on the 5,000 plans with at least 250 participants that represented more than 96% of the premiums paid. In 2015 alone, those larger plans paid $145 million in premiums that could have been avoided ... and 65% of eligible companies paid too much in variable-rate premiums."