Walt Disney, Koch Industries and other companies agreed deals in Luxembourg that could have delivered huge tax savings, a group of investigative journalists has reported.
The new revelations have heightened an international debate on corporate tax avoidance.
The International Consortium of Investigative Journalists (ICIJ) said the two companies engaged in complex restructurings and channelled hundreds of millions of dollars in profits between 2009 and 2013 through Luxembourg subsidiaries that enjoyed tax rates of less than 1%.
The consortium describes itself on its website as a global network of journalists who collaborate on investigative stories.
Its earlier disclosures prompted an EU parliament no-confidence vote on the European Commission's new president Jean-Claude Juncker.
Juncker, who had overseen the Grand Duchy's tax policies for two decades as finance minister and later prime minister, survived the vote.
Luxembourg's finance ministry said today that its system for issuing advance rulings to companies, outlining how the tax authority would treat their transactions, was "compliant with international and national law".
"The way in which these documents were acquired is highly questionable", it added.
Koch spokesman Robert Tappan said "Koch companies conduct their business lawfully and they pay taxes in accordance with applicable laws."
Disney established an inter-company bank in Luxembourg which then extended high-interest loans to operating affiliates in countries such as France, thus reducing their taxable income, the ICIJ said.
Disney spokeswoman Zenia Mucha said the report was deliberately misleading. "Disney's global tax rate has averaged 34% over the last five years. The ruling has not meaningfully affected the taxes we pay in any jurisdiction globally."
Advisory group EY advised Disney and Koch on their arrangements, the ICIJ said. Other companies whose tax deals appear in the latest leaks include Hong Kong-based Hutchison Whampoa, private equity group Warburg Pincus and Microsoft subsidiary Skype.
Microsoft said it followed the law in all the countries where it operated. Warbug Pincus declined to comment.
The ICIJ's first set of Luxembourg revelations, published on November 5, were based on files from accounting group PricewaterhouseCoopers (PwC).
That prompted a UK parliamentary panel on Monday to accuse PwC of organising tax avoidance on an "industrial scale."
In addition to EY, the latest set of documents include files from the other two of the "Big 4" accounting firms, Deloitte and KPMG. KPMG said its code of conduct required employees to act lawfully and ethically. Deloitte was not immediately available for comment.
Tax avoidance is legal but companies which use complex structures to reduce their tax bills are coming under scrutiny from legislators internationally, who have promised to crackdown on the practices.
The European Commission was already investigating the legality of tax deals similar to those revealed by the ICIJ, that countries including Luxembourg, the Netherlands and Ireland agreed with multinationals in recent decades.
The ICIJ leaks have boosted calls for greater harmonisation of European tax laws.