My 401k is currently invested in the company's "Aggressive Growth" fund, which I'm generally happy with. However, the expense ratio is 0.59, which I feel quite high. I looked at the other investment options they offer and the only Vanguard fund they offer is the VFIAX which is weighted to the S&P 500. I would like to move some of my investment to the lower cost Vanguard fund, but am hesitant to move everything to an S&P 500 only fund. I've looked at the other funds that my plan makes available, but not many of them have an expense ratio lower than the one I'm currently in. Any advice for an investment newbie? I'm in the process of reading jlcollins stock series.