An effort to rewrite global tax rules is awaiting a nod of support at a G-20 meeting this weekend in Japan.

The Organization for Economic Cooperation and Development will present the outline for a plan to revamp how multinationals are taxed to the group’s finance ministers. The blueprint, released May 31, would set a global minimum tax and reallocate more of companies’ taxable profits to the countries where their consumers are located.

The meeting will include a half-day session June 8 on digital taxes, bringing together top finance officials from the U.S., China, France, the U.K, India, and others. The OECD is looking for the G-20 to approve a program of work—next steps on the project that include assessing the plans’ impact on countries’ economies, and trying to find consensus among countries that are still deeply divided over how the new rules should work.

“We will need a deal at the political level, based on sound technical recommendations, to come up with a solution which should stabilize the system by removing existing tensions,” Pascal Saint-Amans, director of the OECD’s Center for Tax Policy and Administration, said June 3 at an international tax conference in Washington organized by the OECD and the U.S. Council for International Business.

“And to stabilize the system we need to make sure that governments are much less nervous than they have been over the past few years,” he said.

What Will Be Discussed?

The OECD described two tracks of work in its blueprint.

One set of proposals would allocate more taxing rights—and thus more taxable profit—to “market” jurisdictions, where a company’s users and consumers are located. To find widespread agreement on these proposals, some countries will have to agree to cede some of their tax revenue. Countries disagree on whether these proposals should only target digital businesses—by looking at how users create value for those companies, for example—or address broader changes.

Another proposal would address “race to the bottom” competition among countries to lower their tax rates, by ensuring companies pay at least a minimum rate on their foreign profits.

What’s at Stake?

The OECD’s work started in response to many countries’ concerns that digital companies aren’t taxed enough, or taxed in the right places, under current rules. But the ultimate recommendations, when implemented, will likely affect almost all multinational companies, not just the tech industry.

“This work started with a focus on digital companies,” said Jesse Eggert, a principal at KPMG LLP and a former senior tax adviser with the OECD. “Now, they’re looking at fundamental questions of how to allocate profits between source and residence countries. All of that means that the work now touches taxpayers in every sector, in every industry, in ways that I think couldn’t have been predicted at the beginning of the project.”

A number of countries—including France, the U.K., Austria and Italy—are pursuing unilateral measures that would tax the revenue of tech giants like Facebook Inc. and Alphabet Inc.'s Google, adding urgency to the OECD’s effort.

Governments proposing the measures say they’re a necessary stopgap until a multilateral OECD solution is in place. But opponents of the digital taxes—including the U.S. government and lawmakers, and the tech companies themselves—say the approach will create a compliance headache for companies and tax them on income that’s already being taxed somewhere else.

The tech industry “would absolutely agree with the need” for an OECD solution, said Jennifer McCloskey, vice president of policy at the Information Technology Industry Council. “We’ll try to be as constructive as possible to make sure a good system is developed to protect taxpayer interests.”

A successful OECD outcome could forestall the unilateral measures. But if the OECD fails to reach agreement, unilateral measures could proliferate.

What’s Next?

The OECD is working against an end-of-2020 deadline for a solution that can be implemented—a goal it described as “extremely ambitious” in the May 31 work plan.

All 129 countries involved will have to agree on what the solution will be—which they must do by January in order to meet their deadline, the work plan said. That will mean narrowing the multiple profit allocation proposals down to one approach.

For the OECD’s immediate next steps, “We say, ‘work, work, work’” Gael Perraud, deputy director of European and international taxation at the French Finance Ministry’s Tax Policy Department, told the June 3 conference. He represents France at the OECD and serves as the co-chair of the group’s task force on the digital economy.

If the G-20 approves the program of work, the OECD will begin technical policy work on each of the proposals and begin conducting an impact assessment on the effects of the plans, as it continues trying to find political agreement in the coming months.

It’s important that the OECD solution lasts and countries don’t have to renegotiate these issues in a few years, Perraud said.

That means the assessment should consider the long-term effects of the solution, including how it can stabilize the global tax system and lead to fewer disputes between companies and tax authorities, he said.