Size may be hazardous to the life of a mutual fund. Morningstar's Russel Kinnel, in a column on the fund tracker's Web site, issues a warning to investors, but it may as well apply to mutual funds themselves: Funds may be getting too big for their own good. For one thing, Kinnel says, when a fund is flush with assets, its manager may not have the time or resources to research stocks adequately. Further, a top manager may not be able to handle a large fund alone – which suggests investors may not be getting the expertise they are expecting, or the results for that matter. Kinnel also points to problems with high asset turnover and the fact that many funds may end up following similar strategies. Kinnel notes that in the past five years the number of funds with more than $1 billion has grown by more than 50%, from 730 to 1123.