India's market regulator chief rejected Sunday allegations by US short-seller Hindenburg Research that claimed past offshore investments may have prevented her from properly investigating corporate malfeasance allegations against the Adani Group.

Last year, Adani Group, the sprawling ports-to-power Indian conglomerate, saw billions of dollars wiped from its market value after a bombshell report by the Hindenburg forensic financial research firm accused it of "brazen" corporate fraud.

The family-run conglomerate's founder, Gautam Adani, the world's 12th richest person according to a Bloomberg index of the world's billionaires, denied the allegations made in that report, calling it a "deliberate attempt" to damage its image for the benefit of short-sellers.

Hindenburg claimed that Adani's elder brother Vinod "manages a vast labyrinth of offshore shell entities" in tax havens including Mauritius, Cyprus and several Caribbean islands.

- 'Insinuations' -

The fraud claims wiped more than $150 billion off the group's market value and prompted India's top court to ask the Securities and Exchange Board of India (SEBI) to probe the allegations.

On Saturday, citing whistleblower documents, Hindenburg accused SEBI chairperson Madhabi Puri Buch and her husband of having held investments in offshore funds that Vinod Adani also allegedly used.

"We suspect SEBI's unwillingness to take meaningful action against suspect offshore shareholders in the Adani Group may stem from Chairperson Madhabi Buch's complicity in using the exact same funds used by Vinod Adani, brother of Gautam Adani," Hindenburg said.

It suggested that the regulator may have been "reluctant to follow a trail that may have led to its own chairperson".

The report says the couple opened their account in one fund in 2015.

It added that weeks before her appointment to SEBI as a "whole-time member" in 2017, her husband requested to be the sole operator of the account.

Buch was later appointed as chairperson of the markets watchdog in 2022.

She said her and her husband's "life and finances are an open book", in a statement.

"We strongly deny the baseless allegations and insinuations made in the report," she said.

"All disclosures as required have already been furnished to SEBI over the years," she added.

"We have no hesitation in disclosing any and all financial documents, including those that relate to the period when we were strictly private citizens, to any and every authority that may seek them".

Adani is considered a close associate of Hindu-nationalist Prime Minister Narendra Modi, and opposition parties and other critics say their relationship helped Adani to unfairly win business and avoid proper oversight.