Bad news for U.S. Poloniex clients - it seems that the company owning the platform, Circle, will pull out margin trading for them. The decision was announced in a blog post. Additionally, the company will delist GNO (Gnosis), AMP (Synereo) and EXP (Expanse).
https://blog.circle.com/2018/10/03/poloniex-to-remove-margin-and-lending-products-for-us-based-customers/
It is important to note that U.S. traders will have seven days notice when the decision comes to power, especially since withdrawals will not be possible after that period. The decision came as a plan to revive the Poloniex.