no. no. No. NO. NOOOO! Please don't fall into the active investor trap of trying to pick winners and losers, especially based only on past performance. That 2040 fund is fine. 8% YTD returns is right on the money for index investors. Any idiot can find a fund or stock that has outperformed the market, but what almost nobody has been able to do is beat the market consistently over 10, 15, 20+ years. Sure that UP stock fund is up 40% this year, but will that continue for 10 years? If it goes up 40% this year, what will you say when it tanks 30% next year? You see my point here... It's all about long term future, not YTD, 5 years, 10 years, etc. in the past.
IMO, stick with the 2040 fund.