Abu Dhabi conglomerate International Holding Co. (IHC) said on Monday it would be investing 1.4 billion dirhams ($400 million) into the Indian conglomerate Adani Enterprises' follow-on share offering.

The statement comes as shares in Adani Group companies slumped over $70 billion over three days after US investor Hindenburg Research accused the companies' billionaire-owner Gautam Adani of market manipulation and fraud.

IHC's investment will be made through its subsidiary Green Transmission Investment Holding RSC Ltd., the diversified investor said in the statement on Abu Dhabi's ADX exchange where its shares trade.

Adani Enterprises' $2.5 billion follow-on public offer (FPO) is currently underway and is expected to close on Tuesday.

"Our interest in Adani Group is driven by our confidence and belief in the fundamentals of Adani Enterprises Ltd; we see a strong potential for growth from a long-term perspective and added value to our shareholders," said IHC CEO Syed Basar Shueb.

This is the second investment deal IHC has completed with India's Adani Group after last year's AED7.3 billion investment in three green-focused companies of the Adani Group, including Adani Green Energy, Adani Transmission, and Adani Enterprises, which are all listed on the Bombay Stock Exchange and National Stock Exchange of India.

"The advantage of the FPO is the historical reference for the company's earnings report, company's management, business practices, and much data to bank on before making any investment decision," said Shueb.

(Writing by Brinda Darasha; editing by Seban Scaria)