Bermuda-founded law firm Appleby has denied any wrongdoing in response to the ‘Paradise Papers' leak.
Around half of the 13.4 million hacked files relating to the tax haven industry were sourced from the offshore firm, whose clients have included Barclays, Goldman Sachs, Nike, Apple and Uber.
The ABC reports royals, rock stars and 120 politicians have been exposed in the documents. As have some of the world's most powerful oligarchs.
Appleby has close to 500 employees, including 60 partners, and is present in Bermuda, Isle of Man, Jersey, Guernsey, British Virgin Islands, Cayman Islands, Mauritius, the Seychelles, Hong Kong and Shanghai.
Concerns stem from "risky business" the firm may have taken on.
The BBC says an in-house presentation to staff, which was part of the leak, "appears to acknowledge the company may have taken on risky business, referring to concerns around non-compliance with its regulatory obligations, including anti-money laundering policies".
The Bermuda Monetary Authority, the island's financial watchdog, also reportedly raised concerns in 2015 over Appleby's anti-money laundering and anti-terrorist financing checks and compliance with trust regulations.
However, while addressing inquiries from the International Consortium of Investigative Journalists, which received the cache of files from German newspaper Suddeutsche Zeitung, the firm has vehemently denied any wrongdoing.
"Appleby has thoroughly and vigorously investigated the allegations and we are satisfied that there is no evidence of any wrongdoing, either on the part of ourselves or our clients," it said in a statement.
Appleby has thoroughly and vigorously investigated the allegations and we are satisfied that there is no evidence of any wrongdoing.
"We refute any allegations that may suggest otherwise and we would be happy to cooperate fully with any legitimate and authorised investigation of the allegations by the appropriate and relevant authorities.
"We are an offshore law firm that advises clients on legitimate and lawful ways to conduct their business. We do not tolerate illegal behaviour. It is true that we are not infallible. Where we find that mistakes have happened, we act quickly to put things right and we make the necessary notifications to the relevant authorities.