Rules on political groups in the EP

Political groups are central to the work of the European Parliament. After European citizens elected a new Parliament, political groups are expected to notify their composition by end of June. To form a political group, a minimum of 25 MEPs elected in at least one quarter of the EU's Member States (currently seven) is required.
https://www.europarl.europa.eu/thinktank/en/document.html?reference=EPRS_BRI(2018)630264

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