NEW DELHI (AP) — India’s Adani Group launched a share offering for retail investors Friday as it mulled taking legal action against U.S.-based short-selling firm Hindenburg Research for allegations of stock market manipulation and accounting fraud that caused heavy selling of its stocks this week.

Jatin Jalundhwala, head of the Adani group’s legal department, said late Thursday that the group “was evaluating the relevant provisions under U.S. and Indian laws for remedial action against Hindenburg Research.”

``Clearly, the report and its unsubstantiated contents were designed to have a deleterious effect on the share values of Adani Group companies as Hindenburg Research by their own admission, is positioned to benefit from a slide in Adani shares,” Jalundhwala said.

Hindenburg’s report has prompted investors to dump Adani Group shares, wiping out billions of dollars' worth of market value.

Jalundhwala said the allegations were an attempt by Hindenburg to sabotage Adani’s share offering. Hindenburg Research said in a rebuttal that it would welcome legal action by the Adani group.

“We fully stand by our report and believe any legal action taken against us would be meritless," it said in a statement.

Adani made a vast fortune mining coal as energy-hungry India grew swiftly after its economy was liberalized in the 1990s. Businesses in the conglomerate span industries including construction, data transmission, media, renewable energy, defense manufacturing and agriculture.

The market value of Adani's companies has soared in recent years, one of the reasons Hindenburg said it judged the seven key Adani listed companies to have an “85% downside, purely on a fundamental basis owing to sky-high valuations.”

Its report, “Adani Group: How the World's 3rd Richest Man is Pulling the Largest Con in Corporate History," said Hindenburg was betting against shares in companies within the Adani empire, founded by Asia’s richest man, coal magnate Gautam Adani.

Hindenburg said its report followed a two-year investigation and “listed 88 questions it invited the company (Adani) to answer." Most of the allegations involved concerns about the group's debt levels, activities of its top executives, use of offshore shell companies and past investigations into fraud. So far, Adani had answered none of these questions,’’ it said.

Adani set a price range of 3,112 rupees-3,276 rupees ($38.22-$40) a share for the offering, which closes on Tuesday. Shares in the flagship company Adani Enterprises fell 10% to 3,060 rupees at one point on Friday. Its shares fell 1.6% on Wednesday. Indian markets were closed Thursday for a holiday.

Some of the companies suffered even bigger hits.

Shares in Adani Transmission plunged 19.4% on Friday after sinking 8.1% on Wednesday. Adani Ports and Special Economic Zone Ltd. sank 17.3% on Friday after shedding 6.1% on Wednesday. Other group companies fell between 5% to 20%.