HONG KONG • Asia's biggest private banks boosted their assets under management to a record last year, rebounding from a 2015 contraction, amid acquisitions that swelled some firms' portfolio holdings.

Assets managed by the region's top 20 private banks climbed by 6.1 per cent to US$1.55 trillion (S$2.18 trillion) last year from a year earlier, according to an Asian Private Banker report released yesterday.

The amount contracted 4.7 per cent in 2015 as the region's economic growth slowed and mounting regulatory pressure forced banks to reject some clients.

Last year's figure was bolstered by Bank of Singapore's purchase of Barclays' wealth-management units in Singapore and Hong Kong, and Union Bancaire Privee's acquisition of Coutts International.

Private banks have been seeking to expand in the Asia-Pacific region, where individual wealth surpassed that of North America for the first time in 2015, according to a report by Capgemini .

Merger and acquisition "activity and heavy hiring had a positive effect on a number of banks in terms of scale", Asian Private Banker editor Sebastian Enberg said in an e-mail.

Bank of Singapore's Barclays deal lifted its managed assets by 44 per cent to US$79 billion in 2016 from a year earlier, according to Asian Private Banker.

That lifted the OCBC unit's ranking among the region's private banks to seventh from 11th, the publication said.

It has now joined sixth-ranked DBS Group Holdings as the only Asia-based banks in the top 10, the list shows.

Union Bancaire Privee entered the top 20 for the first time - albeit in 20th place - after its acquisition saw the firm's managed assets soar to US$11.8 billion from US$774 million a year earlier, Asian Private Banker said.

UBS Group retained the top rank with US$286.4 billion in assets, while Citigroup kept its No. 2 spot with US$218 billion of holdings. The top six positions were unchanged from 2015.

BLOOMBERG