This was not only talked about but there are now draft laws in the EU about exactly that

  Article 1c 1. It shall be prohibited for Union central securities depositories to provide any services as defined in the Annex of Regulation (EU) No 909/2014 of the European Parliament and of the Council\* for transferable securities issued after 12 April 2022 to any Russian national or natural person residing in Russia or any legal person, entity or body established in Russia. 2. Paragraph 1 shall not apply to natural persons who are nationals of a Member State or having a temporary or permanent residence permit in a Member State

  Article 1d 1. It shall be prohibited to sell euro denominated transferable securities issued after 12 April 2022 or units in collective investment undertakings providing exposure to such securities, to any Russian national or natural person residing in Russia or any legal person, entity or body established in Russia. 2. Paragraph 1 shall not apply to nationals of a Member State or natural persons having a temporary or permanent residence permit in a Member State

https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELE...