The leak of the Paradise Papers, a trove of 13.4m documents claiming to show how “the rich get richer through offshore manoeuvres”, quickly inflamed both politicians and campaigners.
Bernie Sanders, the US senator, said the leaked data showed how the “international oligarchy” avoided paying its “fair share of taxes”.
Jeremy Corbyn, the UK opposition leader, said society was being damaged by “a super-rich elite which holds the taxation system and the rest of us in contempt”.
But for tax experts, the conclusions were less clear. They said the structures revealed so far in the new cache were very different from those exposed in a previous leak, last year’s Panama Papers.
Pascal Saint-Amans, the top tax official at the Paris-based OECD said: “They are quite different from the Panama Papers.”
He said the schemes in question were mostly, if not totally, legal. “Some are not even questionable from a legitimacy point of view.”
The Panama Papers led more than 70 governments to launch probes resulting, for example, in the ousting of Nawaz Sharif, Pakistan’s prime minister.
The leak also forced Panama, a holdout in an international transparency drive, to bow to global pressure.
Speaking on Monday, British tax officials said 66 criminal investigations had arisen from the Panama leak and that they might retrieve £100m of tax.
But Appleby, the “offshore magic circle” law firm at the centre of the new leak, after the computer servers in several of its offices were hacked, is very different from Mossack Fonseca, whose data featured in the Panama Papers.
The New York Times, a member of the International Consortium of Investigative Journalists, the global network behind both sets of revelations, contrasted the “predominantly elite” clients of Appleby with those of Mossack Fonseca, which it said “appeared to be less discriminating in the business it took on”.
It said, however, that in among the “dull reading” of the new documents, there were some that revealed how multinational companies avoided taxes and how the super-rich hid their wealth.
The fresh leaks will reignite the debate on whether the international financial services industry plays a positive or negative role in the global economy.
For some, there is little doubt that the offshore centres are harmful. Last year more than 300 economists, including the Nobel Prize winner Angus Deaton, signed a letter to world leaders that argued: “The existence of tax havens does not add to overall global wealth or wellbeing; they serve no useful economic purpose.”
But there are also strong defenders of offshore finance, which is often described as an essential cog in a world of increasingly cross-border trade and investment. The “tax neutrality” of havens ensures that individuals from different jurisdictions making collective investments can avoid double taxation.
Mark Pragnell, head of commissioned projects at Capital Economics, a consultancy, said: “Fundamentally, offshore centres facilitate the cross-border economy by helping individuals and organisations do deals across borders.”
Trusts are often used in order to protect minors or high-profile individuals’ rights to confidentiality.
Martin Sullivan, chief economist for Tax Analysts, a non-profit publisher, said: “There is nothing illegal about having a bank account in Bermuda. It’s only a problem if you don’t disclose it on your tax return.”
Offshore centres have, at least in part, shaken off their reputation for secrecy in the wake of an international transparency drive which will result in the automatic exchange of tax data by more than 100 other countries, a process that began in September.
The US has not joined the new system, although it is automatically exchanging certain information under its own automatic exchange rules, known as the Foreign Account Tax Compliance Act.
In June the OECD said “massive progress” had been made over the past year as it revealed there would be no significant offshore centres on the blacklist of “unco-operative tax havens” it had prepared for the G20 group of leading countries.
Angel Gurría, secretary-general of the OECD, said on Monday that the problems shown in the leaks were a “legacy issue” and there was now “quite literally no place to hide”.
But while the OECD is largely satisfied by the progress made by the offshore centres, some governments would like to go much further.
European governments have been split over plans to draw up a tax haven “blacklist”, with London, in particular, opposing some of the efforts. There might also be a renewal of pressure to open up trusts to greater public scrutiny, an issue on which the UK is strongly opposed to further action on privacy grounds.
There could also be a revival of the pressure on British Overseas Territories and Crown Dependencies to introduce central public registers of company ownership.
This proposition, a long time goal of former prime minister David Cameron, was dropped by the previous government, but Britain’s Labour party has signalled it would continue to push for it.
Such a move would delight centres such as Singapore, which compete with the Overseas Territories and Crown Dependencies, according to a lawyer specialising in offshore work who did not wish to be named. “They are rubbing their hands when they think about what might flow from a British own goal on this.”
He argued that “ordinary people” would be losers if Britain’s offshore centres were damaged by a further crackdown because they were widely used by the pension funds on which they depend.
But there remains public support for tackling offshore finance and there is a widespread perception that offshore centres shift the burden of taxation to ordinary taxpayers and give multinational corporations an edge over smaller competitors.
The growing concern about inequality is driving a lot of the debate, according to Mr Saint-Amans: “There is still political and public pressure to fight the tax havens.”