Billionaire Gautam Adani's Ambuja Cements agreed to buy a 47% stake in Orient Cement in a deal valued at $963 million, stepping up acquisitions amid intensifying rivalry with tycoon Kumar Mangalam Birla.

Ambuja Cements Ltd., part of the Adani Group, has agreed to acquire Orient Cement Ltd. in a deal valued at 81 billion rupees ($963 million), as billionaire Gautam Adani continues to snap up makers of the key raw material needed for India’s infrastructure push.

Ambuja Cements , India's No.2 cement maker, said on Tuesday it would buy a nearly 47% stake in rival Orient Cement for 37.91 billion rupees ($451 million), but analysts raised doubts about the deal winning regulatory approval.

Adani Group on Tuesday said it has agreed to acquire CK Birla group firm Orient Cement Ltd in a deal valued at Rs 8,100 crore, as billionaire Gautam Adani-run conglomerate snaps up smaller rivals to challenge India’s top cement maker UltraTech.

The deal values Orient Cement’s operational and ready-to-implement capacity at $58 per tonne, significantly lower than the greenfield set-up cost of $110-120 per tonne. The operational capacity valuation is pegged at $113 per tonne.

India's Ambuja Cements said on Tuesday it would acquire a 46.8% stake in Orient Cement, valuing the company at 81 billion rupees ($963.5 million). The Adani-owned cement maker will buy the Telangana-based company's shares at 395.

Ambuja Cements Ltd., part of the Adani Group, acquired Orient Cement Ltd. for 81 billion rupees ($963 million), as billionaire Gautam Adani continues to snap up makers of the key raw material needed for India’s infrastructure push.