The Norwegian Government Pension Fund Global (GPFG) is linking up with insurer MetLife to co-invest in top-grade office properties in the US.

As its first investment, the partnership is buying One Financial Center in Boston, Massachusetts, in a $700m (€508.3m) deal that closed at the beginning of this month.

Norges Bank Investment Management (NBIM), the sovereign wealth fund’s asset manager, said its share of the purchase was $238m.

The new joint venture between affiliates of NBIM and MetLife will buy class-A office properties in key US markets over an extended period, NBIM said.

NBIM will hold a 47.5% stake in the venture, and MetLife will have the remaining 52.5%.

The Norwegian asset manager said the joint venture is the sovereign wealth fund’s third US-focused real estate investment platform.

MetLife will be the platform’s asset manager, it said.

The Boston property is a 46-storey office block with 1.3m rentable square feet of space, located next to the city’s South Station, NBIM said.

NBIM has acquired its 47.5% share of the property from One Financial Center Equity – an affiliate of Beacon Capital Strategic Partners.

The deal will see MetLife increasing the share of the asset it already holds by 2.5%, it said.