Under DAC6 not every cross-border tax arrangement must be reported. Several conditions must be met before the disclosure obligation arises.
1. Cross-border element
The arrangement must be cross-border. That means it concerns either: 
i)	more than one EU Member State; or
ii)	EU Member State and a third country.
Typical indicators of cross-border relevance include:
i)	the participants are tax resident in different jurisdictions;
ii)	an entity is resident in two or more jurisdictions;
iii)	business is carried out in another jurisdiction via a permanent establishment; or
iv)	activities have an impact on the automatic exchange of information (specifically CRS reporting).
Purely domestic arrangements are outside DAC6.
2. Presence of a hallmark
The arrangement must contain at least one hallmark defined in Annex IV of DAC6.
Category A – Generic hallmarks (e.g. confidentiality clauses, success fee linked to tax advantage).
Category B – Specific hallmarks (e.g. loss-buying, income conversion, circular transactions).
Category C – Cross-border hallmarks (e.g. double deductions, double relief, tax-exempt income, mismatches in valuation).
Category D – CRS avoidance & opaque ownership (e.g. non-transparent structures designed to hide beneficial owners or circumvent CRS reporting).
Category E – Transfer pricing (e.g. use of unilateral safe harbours, hard-to-value intangibles, transfers eroding earnings).
3. Main Benefit Test (MBT) – where applicable
Some hallmarks (mainly categories A, B, and some C) only trigger reporting if the main benefit test is satisfied.
The MBT asks whether, having regard to all relevant facts and circumstances, the main benefit or one of the main benefits that a person may reasonably expect from the arrangement is the obtaining of a tax advantage.
If no tax advantage is a main benefit, then those hallmarks do not apply.
Other hallmarks (such as certain mismatches, CRS avoidance, or transfer pricing arrangements) apply without the MBT.
4. Timeline condition
The arrangement must be reportable within 30 days of:
i)	being made available for implementation; 
ii)	being ready for implementation; or
iii)	when the first step in implementation has been made.
Retroactive reporting also applied for arrangements implemented between 25 June 2018 and 30 June 2020 (the “look-back period”).
5. EU nexus of the reporter
The reporting party (intermediary or taxpayer) must have a sufficient link to the EU:
i)	tax residence in an EU Member State;
ii)	a permanent establishment in an EU Member State; 
iii)	incorporation in, or subject to, the laws of an EU Member State; or
iv)	registration with an EU professional association.