NISA Investment Advisors' Pension Surplus Risk index rose for the second straight month in February, to 7.6% from 7.1%.
The index, which measures the volatility of the funded status of U.S. corporate pension plans, rose to 7.1% in January from 6.7% in December.
The volatility of the asset component of the index rose to 8.8% from 8%, and the liability component, to 7.7% from 7.4%. The average plan funded status fell slightly to 89.4% from 90%.
Over the trailing 12-month period, the index fell 60 basis points while average funded status rose 4.5 percentage points.
The index is a forward-looking estimate of the funded status volatility of the 100 largest corporate pension plans as determined by NISA from publicly available information.