Why is this mutual fund severely lagging the S&P 500 index?

I have a handful of T.Rowe Price mutual funds in an IRA and I’m trying to figure out why the All-Cap Opportunities fund (PRWAX) is underperforming (+0.28% YTD) the S&P 500 index (+10% YTD) so far this year. Like many mutual funds, the top 10 holdings are almost identical to the S&P 500. The same can be said about their Blue Chip Growth fund (TRBCX) at +0.34% YTD. It’s hard to believe that the remaining holdings could be substantially different enough to cause a disparity of 10% with the S&P 500.