In a lengthy report by Coinfirm it was discovered that nearly 70% of cryptocurrency exchanges lacked KYC/AML implementation thus allowing for private and anonymous purchases and sales of bitcoin and other cryptocurrencies. However the trend is changing as more exchanges are now adopting regulations to entice institutional and commercial investors, according to the report’s author.
Sources:
https://www.coindesk.com/most-crypto-exchanges-still-dont-have-clear-kyc-policies-report
https://www.sec.gov/comments/sr-nysearca-2019-01/srnysearca201901-5164833-183434.pdf