Bitmixer.io is one of the most popular bitcoin mixing and tumbling services on the web and caters to large volumes of BTC. The service has been operating since 2014, and the platform was processing 65,000 BTC per month
A statement from the bitcoin privacy giant below from bitcoin.com's article:
“Despite the huge profit we earn, we are closing our activity,” explains Bitmixer. “Let me explain why. I’m bitcoin enthusiast since 2011. When we started this service, I was convinced that any Bitcoin user has a natural right to privacy. I was totally wrong. Now I grasp that Bitcoin is a transparent non-anonymous system by design. Blockchain is a great open book.”
Read Bitcoin.com's article about Bitmixer:
https://news.bitcoin.com/one-of-the-largest-bitcoin-mixing-services-closes-its-doors/
Thread is on bitcointalk forum as to an in-depth reason why:
https://bitcointalk.org/index.php?topic=2042470.new#new
Source(s): Bitcoin.com, Bitmixer.io & Bitcointalk.org