The chief fundraiser and senior adviser to Canadian prime minister Justin Trudeau, Stephen Bronfman is being linked to offshore schemes that may have cost Canada millions of dollars in taxes.
According to the BBC, the leaks suggest that Mr Bronfman's investment firm, Claridge, had moved millions offshore for the Kolber family for more than 20 years.
Tech giant Apple is alleged to have rearranged its affairs, moving the firm holding most of its untaxed overseas cash to Jersey, after changes were made to controversial Irish tax practices, the BBC and Guardian said.
Apple said its new structure did not reduce tax payments in any country and "ensured that our tax obligation to the United States was not reduced".
Where has this data come from?
Much of the new trove of files includes bank statements, emails and loan agreements from Appleby, a firm which helps clients set up in overseas jurisdictions with low or zero tax rates.
Responding to the leak on Sunday, Appleby said there was"no evidence" that it had done anything wrong.
About | Appleby
Appleby is one of the world's largest offshore firms, advising companies, financial institutions, and high-net-worth individuals.
Headquartered in Bermuda but operating in 10 offices across key offshore jurisdictions including the British Virgin Islands, the Cayman Islands, Isle of Man, Jersey, Guernsey, Mauritius and Seychelles.
Other records came from Asiaciti Trust, a family-run offshore specialist based In Singapore, and from 19 corporate registries maintained by governments in jurisdictions that draw the wealthy seeking privacy.
What is the difference between tax avoidance and tax evasion?
Tax avoidance involves companies and people using legal ways and following the rules to reduce their tax bill.
In contrast, tax evasion is an offence and involves illegal ways of paying less tax than required.
The papers claim major global companies have exploited offshore schemes to avoid tax.
In brief | What is a tax haven?
Tax havens are countries or regions where personal and business taxes are likely to be very low, or even non-existent.
As a result, these countries often attract individuals and companies who are seeking to pay less tax than they would at home.
Businesses may move their headquarters to a tax haven, or individuals choose to live there for some or all of the year, to qualify for the lower tax regime.
Some countries or jurisdictions construct tax legislation with the explicit intention of becoming “havens” for those seeking to avoid tax in their own countries.
This gives rise to “tax competition” between nations eager to get businesses to set up within their borders.
The term “tax haven” does not only refer to countries with low tax rates. It can also be used to describe regimes where financial information is kept secret.
This is where jurisdictions choose not to share financial information relating to businesses and individuals with authorities elsewhere.
The Tax Justice Network defines “secrecy jurisdictions” as countries which “use secrecy to attract illicit and illegitimate or abusive financial flows”.
What is the UK's approach to dealing with tax havens?
The Government announced in 2015 that Britain's overseas territories - which include the Cayman Islands and the British Virgin Islands - had agreed to reveal who owns and profits from a company on central registers or "similarly effective systems".
The Foreign Office says it wants UK law enforcement and tax authorities to have unrestricted access to this information while companies and their beneficial owners must not be alerted should an investigation be under way.
But campaigners argue this falls short of the desire to have increased transparency, including David Cameron's previously stated intentions for such registers to be publicly available.
Responding to the papers, Liberal Democrat leader and former business secretary Sir Vince Cable accused Mr Cameron of failing to clamp down on off-shore tax havens.