A sharp increase in volatility for equity markets caused a $93 billion setback in the estimated funding status of the 100 largest U.S. public pension plans as measured by the Milliman 100 Public Pension Funding Index (PPFI). From the end of December 2017 through the end of March 2018, the deficit grew from $1.332 trillion to $1.425 trillion. As of March 31, the funded ratio stood at 71.4%. In aggregate, the PPFI plans experienced investment returns of -0.75% in the first quarter.