Global negotiators attempting to rewrite tax rules for the digital era are tussling over a threshold for corporate revenue as one of the criteria to resolve the thorny issue of how to tax globe-trotting US tech giants like Amazon.com Inc. and Facebook Inc.

European officials are considering a proposal from Joe Biden’s administration to make companies with at least $20 billion in annual revenue pay more of their tax bill in places they operate, while being less enthused that the US offer would limit levies to just 100 firms, according to people familiar with the discussions.

Negotiators also continue to haggle over a profitability threshold for companies to fall in the tax net, particularly a level that would ensure low-margin Amazon pays up, the people said, speaking on condition of anonymity to describe private talks.

Just setting a $20 billion revenue threshold would capture more than 500 publicly traded companies, according to data compiled by Bloomberg. A high profitability level would narrow that list, and previous versions of the OECD plan have shown countries also considering exempting certain industries, including oil and financial services.

Reaching agreement on the revenue and profit parameters for big firms — along with how much of their profits to reallocate — is necessary for a broader tax accord that would also include a global minimum tax on corporate profits, which the US has suggested be at least 15%.

Such a proposal would net more than 48 billion euros ($59 billion) in tax revenue if applied to this year in the European Union, and almost $41 billion in the US, according to projections published on Tuesday by the newly established EU Tax Observatory.

The Biden administration is pushing for a global deal on minimum tax that would help underpin a US tax overhaul aimed at funding its $4 trillion economic-investment agenda over the next decade. The administration wants to strengthen the US’s own minimum-tax rules, including raising the rate to 21 percent.

On Wednesday, the US announced that it was imposing — but immediately delaying for up to 180 days — tariffs in retaliation for duties that the UK, Italy and four other nations placed on internet companies, allowing time for the broader international negotiations.

While the US has given hope to the years-long talks with its proposals since early April, the lingering disagreements underscore the difficulty of finding common ground among nearly 140 countries involved in the Organisation for Economic Cooperation and Development-led discussions.

Officials caution that Group of Seven finance ministers aren’t expected to reach agreement on these specific points during a meeting in London this weekend, and are more likely to signal general progress toward accords at the Group of 20 and the OECD over the next few months.

“I think we have a deal in sight and hopefully it will happen this year,” outgoing OECD secretary general Angel Gurria said Monday as he retired following 15 years at the group’s helm.

The effort is driven by countries’ concerns that current tax rules don’t suitably capture the way digital companies operate — reaching customers and users in countries without the physical presence that is traditionally the standard for taxability.

A growing number of countries, including France and India, have become frustrated with the pace of the OECD effort to address digital taxation and turned to their own measures to capture more revenue from tech giants. But those digital taxes have been met with threats of trade retaliation from the US, under both the Trump and Biden administrations.

French Finance Minister Bruno Le Maire urged G-7 nations “to support a broad agreement on digital tax and minimum tax at Friday’s meeting in London,” according to a statement Wednesday. “This is a decisive step before the G-20 in Venice in early July. It’s within reach. We owe it to our citizens.”

A US Treasury official described the G-7 efforts as building momentum on international tax talks that will culminate next month. The US is uncertain how much detail on global taxation will appear in the G-7 communique, the official said Wednesday, speaking on condition of anonymity. Treasury secretary Janet Yellen traveled to London on Wednesday to meet her G-7 counterparts, her first international trip since taking office.

The first “pillar” of the OECD’s plan addresses the digital tax concerns by assigning a larger share of corporate profits to countries where companies make sales, instead of where they’re based. “Pillar Two” establishes a global minimum corporate tax rate to end tax-rate competition among countries and raise more revenue.

Tricky Talks

Since the project started picking up momentum in 2018, arguments about the scope of the Pillar One rules — defining which companies would see their profits reallocated — have bedevilled negotiators.

Some countries wanted the rules to only apply to tech companies, arguing the current system of tax rules doesn’t fit digital business models. But the US opposed that approach, which would move revenues away from the US because it mostly hit American businesses.

Years into discussions, countries are still debating which companies should be caught in the new rules — particularly as they try to find a way to scope in Amazon.

The e-commerce giant has massive revenues but runs on a low profit margin. It might escape the parameters of the profit-reallocation rules unless they are specially designed to capture it, such as considering the company’s cloud business separately from its retail arm.

Le Maire said last week that resolving the Amazon issue is critical for France. “When I say all important digital companies, it means all important digital companies,” he said, referring to which companies are covered by the plan.

Negotiators are still working to decide the rate of the Pillar Two minimum tax and details of the plan.

By Birgit Jennen, Alessandra Migliaccio and Isabel Gottlieb