Funded levels fluctuated from 85% down to 72% and back up to 82% during first six months of the year.
Asset gain of $308 billion in April-June period lifts estimated funded ratio to 71.2% from 66%.
The funded ratio of the 100 largest US plans fell to its lowest level in over three years.
But market volatility caused by the coronavirus threatens to erase some of the gains.
Record-low rates negate plans’ 15.66% investment return for the year.