But, buy what?
Most investment companies measure their performance against a basket of stocks, the S&P 500. Few ever outperform the 500, and none do so for extended periods. If your company is equaling the return of the 500, kudos unto them. Which brings up the suggestion that a mutual fund that mirrors their purchases with the makeup of the 500 index (these and other firms mirroring other indexes are called index funds) will, by definition, mirror the return of the 500. These are S&P 500 funds, and like most other index funds, since there is no need to hire and pay for market analysts to determine what stocks to buy, it figures the expense of running an index firm would be very low. And that turns out to be true.
Best buy for risk/performance and lowest fees? An S&P 500 index fund.