The move sees Citywire AA-rated Geoffrey Wong, who had worked on the portfolio management team, charged with final decision making authority as of March 1.
Wong has 29 years of investment experience and is head of global emerging markets and Asia Pacific equities at the company.
A spokesperson for UBS said the change was designed to make manager roles consistent across different channels and in different regions.
However, the spokesperson said Antonioli remains a portfolio manager in the global EM strategy committee, as well as head of LatAm and EMEA equities, and has day-to-day involvement on the fund.
Antonioli had seen his funds responsibilities increased over the summer when UBS chose to roll the Emerging Markets Rising Giants fund into his Emerging Markets High Dividend fund, after the former fund failed to accrue a workable level of assets.
He was also assigned to take on the Emerging Markets Growth fund at the start of 2016. This saw him replace Joseph Devine as lead manager and install his own investment process, known as HALO. This stands for High Alpha Long Only.
On a three year basis to the end of February 2017, the UBS Global Emerging Markets Opportunity fund returned 15.6% in US dollar terms. This compares to a 5.2% rise by its Citywire-assigned benchmark, the MSCI EM Emerging Markets TR USD, over the same period.
*This article was updated on March 24 to reflect that Antonioli had not stepped down from the fund but final decision-making authority now sits with Wong.