A Republican committee at the statehouse today heard from experts on IPERS, the Iowa Public Employee Retirement Fund.
IPERS has unfunded liabilities of $5.6 billion.
But officials recently updated certain assumptions, including expected investment returns, that could push the projected shortfall higher.
The new assumptions foresee a 7 percent return on investments, down from an earlier estimate of 7.5 percent.
That means unfunded liabilities in the pension fund could approach $7 billion.