M&G Investments is replacing Aled Smith with John Weavers as the manager of the M&G American fund.
At the time of replacement the fund will also renamed as the American Dividend fund and run in a similiar fashion to the M&G Global Dividend fund, subject to regulatory approval.
Morningstar downgraded the £797.8m fund from bronze to neutral in April of last year.
At the time of the downgrade Morningstar analyst Karen Jones said: “We are concerned that stock selection [on the M&G American fund] has been weaker over recent years and the fund’s return profile has been more volatile than we would have expected.”
The fund has struggled recently and has had prolonged period of underperformance. In the past five years the fund has returned 78.7 per cent, compared to the IMA North America sector average, which returned 91.5 per cent.
Last year it returned 16.8 per cent, compared to the sector avearge of 17.7 per cent.
M&G said Mr Smith would stay at the asset manager and continue to run his other funds.