Know your customer (KYC)
Plain definition. Under FINRA Rule 2090, know your customer means a brokerage firm must use reasonable diligence to learn and keep the essential facts about every customer.
Technical definition. FINRA Rule 2090 requires every member to “use reasonable diligence, in regard to the opening and maintenance of every account, to know (and retain) the essential facts concerning every customer and concerning the authority of each person acting on behalf of such customer.” The rule’s supplementary material treats as essential the facts needed to effectively service the customer’s account, follow any special handling instructions, understand the authority of each person acting for the customer, and comply with applicable laws, regulations and rules. The rule was adopted by SR-FINRA-2010-039 and amended by SR-FINRA-2011-016, effective July 9, 2012.
On this site
On this site, Know your customer (KYC) comes up in How is XRP classified and regulated outside the US (EU, UK, Japan, Singapore, Canada)?, How do buying and selling XRP work, and where can people do it?, How do I check that a crypto platform is registered and legitimate?, Why does the exchange want my ID? and Are people really being attacked physically for crypto?.
Source
2090. Know Your Customer | FINRA.org (finra.org), read October 1, 2026.
Pages that cover Know your customer (KYC)
- How do I limit the personal data that links me to my crypto holdings?
- Why does the exchange want my ID?
- How do buying and selling XRP work, and where can people do it?
- How is XRP classified and regulated outside the US (EU, UK, Japan, Singapore, Canada)?
- Are people really being attacked physically for crypto?
- How do I check that a crypto platform is registered and legitimate?