Core funds, which invest in both growth and value stocks, have an edge over growth-focused funds in their 10-year performance, but growth funds have been catching up since 2013. Value funds have lagged well behind. Here’s how it played out: A $10,000 investment in the average growth mutual fund on March 31, 2005, would have more than doubled to $24,333 by June 29 this year, according to Morningstar Inc.