I don't know how many times this question is asked from time to time. A seller or buyer may request that the broker he uses to buy or sell not be revealed. It is then reported as anonymous. It could be any of the numerous brokerages. Hope this helps........

Definition of 'Anonymous Trading'

Visible bids and offers on the market without the identity of the bidder and seller being revealed.

Read more: http://www.investopedia.com/terms/a/anonymoustrading.asp#ixzz1jBiNPh8o

Investopedia explains 'Anonymous Trading'

Anonymous trades allow the high profile investors to execute transactions without the scrutiny and speculation of the market.

Read more: http://www.investopedia.com/terms/a/anonymoustrading.asp#ixzz1jBiVl55A