Morningstar has downgraded the Sequoia fund, a $4.2 billion fund that launched in 1970 with the support of Warren Buffett, from a bronze to a neutral rating, according to an article in CityWire.

The fund was co-founded by Bill Ruane, whose friendship with Buffett began in 1950 when they met at Columbia University. David Poppe, chief executive of Ruane’s firm, had led the fund since 2016, but retired in 2018, triggering the rate reduction.

According to Morningstar associate research analyst Mike Voila, “Process tweaks since the year-end 2018 departure of former manager David Poppe have not been fully tested.” He wrote, “The fund continues to earn an above average people pillar rating, in large part because of its leadership of four-co-managers who are well established at the firm but nevertheless only in their 40s, suggesting stable leadership for the foreseeable future.”