Qatar Investment Authority (QIA) has approached banks for a loan of as much as $2 billion to finance its acquisition of BlackRock’s Asia Square Tower 1, according to three people with knowledge of the matter.

The sovereign wealth fund has held preliminary talks with banks to borrow between $1.5 billion and $2 billion, the people told Bloomberg, asking not to be identified because the information is private.

Talks with potential lenders are at an early stage and QIA has not finalised the timeline for the borrowing, they said.

QIA announced an agreement to purchase the office tower from BlackRock last week for S$3.4 billion ($2.5 billion), marking the biggest office transaction in Singapore.

BlackRock, the world’s largest asset manager, had to settle for a lower price than it had originally anticipated for the 43-storey tower, whose tenants include Citigroup and KKR & Company, as rents in the city state decline amid slowing economic growth and rising supply.

QIA, which manages investments for the natural gas-rich nation, has invested about $38 billion in property around the world, with $21.7 billion in office transactions and $7.5 billion for hotels, including the 2014 purchase of the St. Regis Rome, according to Real Capital Analytics.

A spokesman for the QIA declined to comment.-Bloomberg