Abu Dhabi Investment Authority (Adia) has acquired a 16.7 per cent stake in Scotia Gas Networks (SGN) from the UKs SSE.
The stake is worth £621m ($760m).
The transaction will be completed by the end of October 2016, and will be settled in cash.
SSE will retain a 33.3 per cent share. It acquired a 50 per cent equity stake in SGN in 2005 for a total of £505m.
Adia aims to invest between 1 and 5 per cent of its portfolio in infrastructure.
SGN manages the network that distributes natural and green gas to 5.9 million consumers in Scotland and the south of England.
SGN manages £5bn worth of assets, and had a turnover of £1.1bn in the year ending March 2016. It had an operating profit of £512m.