"The funded status of the 100 largest corporate defined benefit pension plans improved by $80 billion during February as measured by the Milliman 100 Pension Funding Index (PFI). The deficit fell to $303 billion from $383 billion at the end of January, due to an increase in the benchmark corporate bond interest rates used to value pension liabilities and robust investment gains. As of February 28, the funded ratio increased to 83.3%, up from 79.6% at the end of January."