On October 18, 2019, Poloniex announced spinning off from Circle into a new company, Polo Digital Assets, Ltd. Poloniex would be backed by a “major” Asian investment group. While the announcement said that this investment group would focus on global crypto traders, those traders do not include U.S. based traders.
Beginning October 18, 2019, U.S. based users will no longer be able to create and setup an account on Poloniex. Then, as of November 1, 2019, trades will no longer be possible, the message advised U.S. users to not deposit funds to Poloniex accounts. Funds will be available for withdrawl through Circle until mid-December, according to the announcement.
Some have speculated Justin Sun, Tron Foundation founder and CEO of BitTorrent was looking to buy Poloniex. This was soon put to rest when in a tweet Justin Sun responded:
Poloniex, founded in 2014, was purchased by Circle in 2018 for $400 million USD.
The Poloniex announcement also includes as Q&A section which you can read here