The ratings agency said its rationale for both downgrades what that: "In the context of an increasingly competitive global equity sector OBSR feels the fettered nature of the product slightly limits the appeal of the fund such that an A rating is more appropriate."
At the same time, OBSR announced the introduction of the Aberdeen Ethical World Fund to the service, awarded an A rating.
It said: "[We] hold the Edinburgh-based global equity team in high regard and have confidence in their efficient utilisation of the firm’s global resources.
"The team’s quality bias and conviction led portfolio construction, whereby risk is viewed in absolute terms rather than relative to the fund’s index, has served investors well.
"While the ethical screening can lead to structural biases, these have not inhibited the fund’s performance over the long term and the team has demonstrated it can outperform a diversified index as well as a peer group of ethical funds through time."
OBSR said it believes the fund is an attractive option for investors seeking an ethically invested global equity fund.
The changes to the ratings followed a meeting on the 9 February.
