Antonioli, who is a named manager on six funds at the Swiss group, is replaced as the sole lead on the fund by Geoffrey Wong, who assumed responsibility on March 1.
Wong brings with him 29 years of investment experience and is head of global emerging markets and Asia Pacific equities at the company.
A spokesperson for UBS confirmed the manager change but would not elaborate on the reason for the switch. Antonioli remains on the five other funds under his charge, which cover both emerging markets and global equity income.
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.