UBS Group AG said on Tuesday that it expects central bank and sovereign wealth fund assets will decline by $1.2 trillion by the end of the year as China and oil-producing countries including Russia and Saudi Arabia use their foreign exchange reserves to boost the economic growth.

Massimiliano Castelli, head of global strategy at UBS Asset Management, said in a phone interview with Bloomberg on Tuesday that the decline in sovereign assets is likely to continue into next year.

UBS said that central banks and sovereign wealth funds totalled more than $18 trillion at the end of 2014.