Adani Group has received regulatory approval for an almost 311.6 billion rupees ($3.9 billion) open offer to buy the remaining shares of two Indian cement maker.

Gautam Adani, has offered to buy 26 per cent of Ambuja Cements Ltd. for ₹ 385 per share and the same stake for ₹ 2,300 per share of ACC Ltd.

Earlier in the day about the ports-to-power conglomerate getting a nod from Securities & Exchange Board of India for this open offer citing people familiar with the development.

Adani's open offer price for Ambuja is at 6 per cent discount compared to Thursday's closing price while that for ACC is at a 1 per cent discount.

The Holcim transaction is set to propel the Adani Group to become India's second-largest cement producer virtually overnight in what's an extremely fragmented and competitive market.

Holcim in May agreed to sell its 63 per cent stake in Mumbai-listed Ambuja Cements to Adani Group, which said then that it plans to spend to spend about $10.5 billion on the stake purchase.

As part of the deal, Adani will inherit Ambuja's controlling stake in another publicly traded cement producer, ACC, and will buy Holcim's direct 4.5 per cent holding in the unit.