See also another post, found here on SN, with an article on this from Decrypt:
Nexo Under Investigation in Bulgaria for Alleged Money Laundering, Tax Offenses #121271 https://decrypt.co/119006/nexo-under-investigation-bulgaria-alleged-money-laundering-tax-offenses

Here are some additional articles on this:
Police Operation against Cryptocurrency Company NEXO in Bulgaria’s Capital (UPDATED) https://m.novinite.com/view_news.php?id=218388

Crypto Lender Nexo Targeted in Bulgaria Probe Into Alleged Money Laundering, Tax Violations https://www.coindesk.com/business/2023/01/12/nexo-subject-to-investigation-in-bulgaria-over-alleged-money-laundering-tax-offenses [Archive]
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See also another post, found here on SN, with a first-hand account related to this Nexo topic:
Bulgarian law enforcement raids offices of cryptocurrency firm Nexo #121376
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Here's the Tweet from Nexo that kicked off a Twitter thread where they claim things are fine.
Over the years, we have turned down a lot of business because Nexo never makes compromises with regard to our very stringent anti-money laundering and know-your-customer policies. But we have always known that this is how you build a sustainable business. 1/
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There have been plenty of warnings to avoid Nexo!
🧵 Is Nexo Next? Otteroooo does a deep dive! #38828 https://twitter.com/otteroooo/status/1540862675306967042 [Nitter]
Is Nexo going to be the next surprise collapse ? #101161
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