• Gautam Adani, one of the world's richest men, withdrew Adani Enterprises' $2.5 billion share offering.
• Shares of Adani Enterprise were routed, falling 28% on Wednesday.

On Wednesday, Gautam Adani announced he's scrapping his firm's $2.5 billion equity sale.

He withdrew the offering for shares in Adani Enterprises, the flagship of the Indian conglomerate Adani Group, after the stock tanked by nearly 30%.

Breaking his silence to the media, Adani said, "Today the market has been unprecedented, and our stock price has fluctuated over the course of the day. Given these extraordinary circumstances, the Company's board felt that going ahead with the issue will not be morally correct."

In a Jan. 24 report, short seller Hindenburg Research alleged that "Adani Group has engaged in a brazen stock manipulation and accounting fraud scheme." The report went on to raise concerns around the debt and valuations of seven Adani companies.

Adani Group has denied the allegations, saying they have "no basis" and stem from an ignorance of Indian law. The group has always made the necessary regulatory disclosures, it added.

Speculation is growing that the Securities and Exchange Board of India (SEBI) will conduct some type of investigation into Adani's businesses.

"My understanding is that a cancellation would mean a mandatory SEBI inquiry," said Pramit Chaudhuri, Eurasia Group's head of South Asia practice, to CNBC.

Chaudhuri, like many, said he was "surprised" to see Adani scrap plans after achieving the $2.5 billion target.

The stunning reversal caps a week in which Adani went on a full mission to ensure his equity sale was successful following immense pressure tied to his falling stock price.

Adani tapped high net worth individuals inside India and looked to the Middle East as well. International Holding Co., an Abu Dhabi-based conglomerate, contributed $400 million to the deal. It was widely seen as a vote of confidence. Goldman's trading desk participated in the deal as well, a source familiar with the matter told CNBC. Adani Enterprises' stock ended higher on Tuesday following news of the fully subscribed $2.5 billion offering.

Investors woke up to an ugly picture on Wednesday when Adani Enterprise's stock plunged, falling by as much as 28% and prompting Adani to cancel his equity sale.

"We are working with our Book Running Lead Managers (BRLMs) to refund the proceeds received by us in escrow and to also release the amounts blocked in your bank accounts for subscription to this issue," added Adani.

The move also raises questions about where else Adani will look for financial support.

As CNBC reported, Adani has established relationships with a slate of international banks and private equity investors. The tycoon, once the second richest person in the world, has slipped to the 13th position in the Bloomberg Billionaires Index as of Feb. 1.