Multilateral Instrument: How the MLI Modifies Tax Treaties and Minimum Standards

The Multilateral Instrument, formally the Multilateral Convention to Implement Tax Treaty Related Measures to Prevent Base Erosion and Profit Shifting, is an OECD-developed treaty that lets governments update thousands of bilateral tax treaties at once instead of renegotiating each one. As of January 2026, the multilateral instrument for tax treaties had 107 signatories and parties and covered roughly 1,950 bilateral agreements worldwide.¹ It entered into force on July 1, 2018, and its first provisions began affecting real tax outcomes on January 1, 2019.²

How the MLI Changes Treaties Without Replacing Them

Renegotiating a bilateral tax treaty the traditional way takes years. Two governments rework the text, run it through their legislatures, and wait for ratification. Most countries have dozens of treaties, so updating a whole network one at a time is impractical.

The MLI works differently. It does not replace existing treaties. It creates a layer of standardized rules that sits on top of them and modifies how specific clauses apply. The core protections against double taxation remain in place. What shifts are the provisions dealing with treaty abuse, dispute resolution, and definitions that multinational corporations have used to reduce tax bills.²

Because the MLI overlays rather than rewrites, reading a modified treaty means reading two documents together: the original bilateral text and the MLI provisions that apply to it.

Which Treaties the MLI Actually Modifies

A bilateral treaty only becomes a “Covered Tax Agreement” when two conditions are met. Both partner countries must be parties to the MLI, and both must have specifically listed that treaty in their formal notification to the OECD, which acts as depositary. If one country lists the treaty and the other does not, nothing changes.

Even for Covered Tax Agreements, the optional parts of the MLI only take effect where both countries make compatible choices. If Country A opts into a provision and Country B files a reservation against it, that provision does not modify the treaty. Neither side can push a rule onto its partner through the MLI. Where there is no match, the original bilateral language stays in force for that issue.³

The Minimum Standards Every Party Must Adopt

Some provisions are non-negotiable. Every country that joins the MLI accepts them, and they apply to all of its Covered Tax Agreements.

Anti-Abuse Preamble Language

Article 6 inserts preamble language into every Covered Tax Agreement stating that the treaty intends to eliminate double taxation “without creating opportunities for non-taxation or reduced taxation through tax evasion or avoidance (including through treaty-shopping arrangements).”⁴ Preamble language influences how courts and tax authorities interpret ambiguous provisions, so making the anti-avoidance purpose explicit gives authorities stronger footing to challenge abusive arrangements.

Principal Purpose Test

Article 7 introduces the Principal Purpose Test as the default anti-abuse rule. A treaty benefit can be denied if it is reasonable to conclude that obtaining the benefit was “one of the principal purposes” of an arrangement or transaction, unless the taxpayer shows that granting the benefit would still be consistent with the treaty’s object and purpose.⁴

The PPT targets treaty shopping, where a company routes income through a country it has no real connection to solely because that country’s treaty offers a lower withholding rate. Countries can supplement or in some cases replace the PPT with a Limitation on Benefits clause, but the PPT is the fallback everyone accepts.

Access to the Mutual Agreement Procedure

Article 16 standardizes the process for resolving disputes when a taxpayer believes they are being taxed in a way that conflicts with the treaty. A person can present their case to the tax authority of either country within three years of first learning about the problematic taxation.⁴ The two tax authorities then try to resolve the issue by mutual agreement. Missing the three-year window forfeits access, so anyone dealing with a cross-border tax dispute should track that clock carefully.

Optional Provisions Countries Can Adopt or Reject

Beyond the minimum standards, the MLI offers a menu of optional rules. This flexibility is what makes broad participation politically feasible, because a country can sign on to the core anti-abuse framework without being locked into every rule. When a country wants to opt out of a specific article, it files a formal reservation.

The optional provisions cover several recurring abuse patterns:

Article 3 addresses income flowing through entities that one country treats as tax-transparent (like a partnership) and the other treats as a separate taxpayer, limiting treaty benefits to income the granting country actually treats as income of one of its residents.⁴
Article 4 handles corporations that qualify as tax residents of two countries at once, requiring the tax authorities to determine residency by mutual agreement and denying treaty benefits until they do.⁴
Article 8 requires a parent company to hold its ownership stake in a subsidiary for a continuous 365-day period including the payment date before qualifying for a reduced dividend withholding rate, blocking short-term acquisitions timed to capture a single dividend.⁴
Article 9 lets the country where real estate sits tax capital gains on the sale of shares in an entity whose value came primarily from that real estate at any point in the 365 days before the sale, closing a technique that avoided property-country tax by selling shares instead of the underlying land.⁴
Articles 12 through 15 broaden when a foreign company is treated as having a taxable presence, or permanent establishment, in a country. They catch commissionnaire arrangements where a local agent habitually plays the principal role in concluding contracts without technically signing them, narrow the traditional exemptions for preparatory or auxiliary activities, and block companies from slicing one business operation into small functions across separate locations to stay under the threshold.⁴

Each of these applies to a given treaty only where both partners have accepted it.

Mandatory Binding Arbitration

Part VI of the MLI adds an optional arbitration mechanism. When a taxpayer files a dispute under the Mutual Agreement Procedure and the two tax authorities cannot resolve it within two years, the taxpayer can require the unresolved issues to go to arbitration. The decision binds both countries unless the taxpayer rejects the outcome.

Take-up has been selective. As of January 2026, 22 jurisdictions had opted into Part VI, including Australia, Canada, France, Germany, Japan, the Netherlands, Singapore, Spain, Switzerland, and the United Kingdom.¹ Because arbitration only applies where both treaty partners have opted in, the number of treaty pairs actually covered is smaller than the country list suggests. Countries can also file reservations narrowing the categories of issues eligible for arbitration.

When the MLI Actually Starts Changing Tax Bills

Signing the MLI is only step one. A country must ratify it through its domestic legislative process. After it deposits its ratification instrument with the OECD, the convention enters into force for that country on the first day of the month following a three-month waiting period.⁴

Entry into force is not the same as entry into effect. Under Article 35, when modifications begin changing actual tax outcomes depends on the type of tax:

For withholding taxes deducted at source on payments to non-residents, changes apply starting January 1 of the calendar year after the MLI has entered into force for both treaty partners.⁵
For all other taxes, such as corporate income tax, changes apply for taxable periods beginning on or after six months from the date the MLI has entered into force for both partners.⁵

The reference point is always the later of the two countries’ entry-into-force dates. If one country ratified years ago and the other just finished, the clock starts from the later date. Different treaty pairs within the same country’s network can therefore have different effective dates.

How to Check a Specific Treaty

Reading the MLI alongside a bilateral treaty to work out the combined result is difficult. To help, the OECD has issued guidance for “synthesized texts,” documents that reproduce the original bilateral treaty with the applicable MLI modifications inserted next to the affected provisions.⁶

Countries are not legally required to publish synthesized texts, and the OECD’s own guidance notes that developing them “is not a prerequisite for the application of the MLI.”⁶ The synthesized version has no independent legal force. The authoritative text remains the MLI applied alongside the original treaty. Even so, many countries have produced them, and they are often the fastest way to read a modified treaty.

To confirm which specific provisions apply between any two countries, the OECD’s MLI Matching Database is the practical tool. It shows the matching outcomes for each pair of signatories, together with the reservations and choices each country has filed and how those positions have changed over time.⁷

Why the United States Is Not a Party

The United States helped negotiate the MLI but did not sign it. Because the instrument only modifies treaties where both partners are parties, no U.S. bilateral tax treaty has been directly modified by the MLI.

Most U.S. treaties already contain detailed Limitation on Benefits clauses, rules-based provisions that restrict treaty access to residents with genuine economic ties to a treaty partner. These predate the MLI and cover similar ground to the Principal Purpose Test, though they work through objective criteria rather than a subjective purpose analysis.

The MLI can still affect U.S. multinationals indirectly. When a U.S. company operates in two foreign countries that have both adopted the MLI, the treaty between those two countries may be modified, changing withholding rates, permanent establishment thresholds, or dispute procedures that affect the company’s foreign subsidiaries. Tax teams at U.S.-headquartered multinationals need to track MLI modifications in every jurisdiction where they operate, even though the home country never signed.

1
OECD. Signatories and Parties (BEPS MLI Positions)
2
OECD. BEPS Multilateral Instrument
3
OECD. Explanatory Statement to the Multilateral Convention to Implement Tax Treaty Related Measures to Prevent BEPS
4
OECD. Multilateral Convention to Implement Tax Treaty Related Measures to Prevent BEPS
5
Action 15 Multilateral Instrument. Entry into Force and Effect
6
OECD. Guidance for the Development of Synthesised Texts
7
OECD. BEPS MLI Matching Database