Emma is a portfolio manager overseeing an equity fund with a focus on large-cap U.S. stocks. To measure the fund's performance, she decides to use a benchmark for comparison. Emma has access to two potential benchmarks: the S&P 500 Index and a mutual fund that focuses on large-cap U.S. stocks.

After reviewing the potential benchmarks, she wonders which would be the most suitable for her fund. What considerations should Emma take into account when choosing a benchmark for performance evaluation?