KKR & Co., Global Infrastructure Partners and Stonepeak Partners have jointly made a binding offer for a controlling stake in Deutsche Telekom AG’s 20 billion-euro ($21 billion) towers unit, people familiar with the matter said.

They’re competing with a consortium of Canadian investment firm Brookfield Asset Management Inc. and Spain’s Cellnex Telecom SA, which made a confirmatory bid for part of the Deutsche Telekom business, the people said, asking not to be identified because the information is private.

Private equity firms are drawn to telecoms infrastructure because of its ability to generate steady, long-term returns. KKR raised $17 billion for its latest global infrastructure fund earlier this year, while GIP is targeting $25 billion for what would be the world’s biggest pool of capital dedicated to infrastructure investments.

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