The European Union has authorized a batch of countries outside the bloc to offer clearing and trading of securities to EU firms, under a regime that Britain may also have to use after Brexit.
The EU's executive European Commission said on Friday it has granted so-called equivalence to the clearing houses of India, Brazil, New Zealand, United Arab Emirates, Dubai and to those of Japan specializing on commodities.
The Commission has also decided that rules on trading venues in Australia, Canada, Japan and Singapore are equivalent to the EU's.
That means clearing houses and exchanges in those countries can now serve EU-based customers, because their home rules are equivalent or equally robust.
If Britain pulls out of the single market when it leaves the EU, lawyers say, seeking a similar equivalence decision from Brussels may be the only realistic option for its banks to continue serving continental customers.
But a Commission official stressed equivalence decisions are taken "case by case" and no conclusions should be drawn concerning Britain and its talks on splitting from the EU, which are due to start by the end of March.
The official also insisted it usually takes "a long period, often years", for the Commission to conclude its assessment of a foreign legal regime.
Brussels can also withdraw equivalence status at short notice, making the regime impractical over the longer term in its current form.
Once a country is deemed equivalent, its financial firms who want to operate in the EU must also seek approval.
Clearing houses stand between two sides of a derivatives transaction, ensuring its completion even if one side goes bust.
Financial firms from the United States, Switzerland, Hong Kong, Singapore, Australia and other major jurisdictions have already been granted equivalence status in the EU in past months and years.