MADRID (Reuters) - Spain's ACS is close to striking a 23 billion euro ($26.8 billion) partnership with BlackRock's ( BLK ) Global Infrastructure Partners to develop data centres, newspaper Expansion reported on Thursday, citing unnamed market sources.

Under this agreement, the U.S. asset manager GIP is set to take a 50% stake in the ACS Digital & Energy unit, Expansion said, consisting of 5 billion euros in equity capital - to be contributed progressively - and 18 billion euros in debt.

ACS declined to comment and neither GIP nor BlackRock ( BLK ) immediately responded to Reuters' requests for comment.

The report comes as surging demand for AI computing and limited power capacity is driving valuations for digital infrastructure to record levels.

ACS had targeted its data centre business to reach a valuation of between 3 billion and 5 billion euros by 2030. The reported partnership with GIP would price it at the high end of that range.

The Spanish construction company is set to update its data centre strategy at an investor day on Friday.

GIP, which manages more than $180 billion in assets globally, last month participated in the $40 billion acquisition of U.S. data centre firm Aligned along with Microsoft ( MSFT ) and Nvidia ( NVDA ).

Major tech companies are on track to spend $400 billion on AI infrastructure this year, according to Morgan Stanley estimates.

($1 = 0.8575 euros)