China’s State Administration of Foreign Exchange is the entity behind a mysterious 5 per cent stake in EDP, the Portuguese utility facing a €9bn takeover bid from China Three Gorges.

The stake controlled by Safe, while small, has had a big impact because it has prevented other potential bidders such as European utilities from trying to step in with rival offers, according to bankers involved.

CTG is attempting to acquire EDP, Portugal’s largest listed company, with a low-ball offer that represents a premium of just 4.8 per cent which has been rejected by the EDP board as too low.

The Chinese state-owned utility already owns more than 23 per cent of EDP shares and sits on its board, after a rescue deal in 2011 that helped the Portuguese group recover after the financial crisis.

The influence of CTG’s existing shares has been augmented by a 5 per cent stake owned by a little-known entity, CNIC Corporation, so that Chinese state-controlled groups control a total of 28 per cent of EDP’s shares.

CNIC is a Hong Kong-registered business majority owned by Safe, the central regulator responsible for managing China’s foreign reserves.

Corporate records reviewed by the Financial Times showed that Safe, along with state-controlled China Reform Holdings, owned CNIC through two Hong Kong-based funds.

The presence of Safe in the deal underscores the backing of the Chinese state and the strategic importance of the proposed EDP acquisition, which CTG hoped to use as a base to build a global renewables powerhouse.

“[The deal] is a culmination of a strategy of alignment of interests,” said Tim Buckley, a director at the Institute for Energy Economics and Financial Analysis, referring to CTG’s many years of involvement and investment in EDP.

“I see this as China’s going global. They are building a global network not by military adventurism, but by economic imperialism,” he added.

CTG and EDP declined to comment.

Safe has become a major investor in overseas projects led by Chinese companies, often as a limited partner. It is one of the primary backers of the Silk Road Fund, a Beijing-based investor in development projects in low-income countries.

China Reform Holdings has also recently become a prominent backer of funds that invest in technology assets, including in Canyon Bridge, a private equity fund that was blocked by the US government from buying semiconductor group Lattice last year.

CNIC and Safe did not respond to requests for comment on the matter. CTG said in its preliminary announcement that the acquisition offer came only from CTG, and that CNIC would decide on the offer in its own right.