A new report from Oxfam estimates that at least $18.47 trillion is being held by individuals in so-called "tax haven" countries across the globe. The international agency says that a large bulk of that (approximately $12.29 trillion) can be traced to the EU. Oxfam says if you were to add all of that up, it'd be enough to end extreme poverty twice over. "These figures put the UK at the centre of a global tax system that is a colossal betrayal of people here and in the poorest countries who are struggling to get by, and put the government on the side of the privileged few," said Emma Seery, Oxfam's Head of Development Finance and Public Services. How reliable Oxfam's estimate is remains unclear; the very nature of tax avoidance makes a solid figure difficult to ascertain.

Everyone agrees something must be done, but finding common ground may not be easy

Nonetheless, as European leaders assemble in Brussels to discuss tax practices of Apple, Google, Starbucks, Amazon, and other large-scale companies, Oxfam is offering its own list of suggestions. The agency is calling for a blacklist of tax havens, and is urging EU states to forge more imposing sanctions against tax havens and businesses that take advantage of them.

The prospects of any meaningful (and global) shifts in tax handling stemming from the Brussels talks are long. Representatives from numerous member states have each threatened to veto proposals that are misaligned with their own interests. Still, the shared consensus among leaders is that timing is critical. "In times of tight budgetary constraints and expenditure cuts, combating tax fraud and tax evasion is more than an issue of tax fairness," reads the invitation to the Brussels meeting. "It has become essential for the political and social acceptability of fiscal consolidation." The US is also putting a microscope on tax practices of major corporations: Apple CEO Tim Cook testified before Congress Tuesday, flatly stating that Apple pays "every single dollar" of its owed taxes.