A Financial Timesreport reviewed the record of some of the oldest mutual funds and asked their managers the key to their success. Some of the answers – consistency, balanced approach -- were not surprising. The MFS Massachusetts Investors is the oldest U.S. mutual fund, launched in 1924. An MFS official quoted in the report said the fund has focused on the long term and protecting capital in tough markets and has never been a “flavor of the month” fund. Vanguard said low costs and a disciplined, balanced approach has helped its Vanguard Wellington Fund persist over time. An official at Capital Group pointed to a consistent approach and results for its American Funds Investment Company of America. Robeco and Pioneer officials cited ESG investing among the several factors that made their funds successful.