Washington State Investment Board, Olympia, on Thursday committed up to $500 million to Global Infrastructure Partners III, spokeswoman Tish Day said.
The GIP fund is targeting $12.5 billion and will invest in large-scale infrastructure assets on a global basis.
The commitment is subject to final negotiation of terms and conditions.
It will be the second time the $106.9 billion WSIB has invested with GIP, having previously committed $250 million to Global Infrastructure Partners II in 2012.