Is Bittrex legal in the US?

Bittrex, a US-based cryptocurrency exchange, has faced legal challenges from the SEC. The exchange was charged with operating as an unregistered securities exchange and reached a settlement with the SEC, agreeing to pay $24 million in fines. However, Bittrex has since announced its exit from the US market and filed for bankruptcy, indicating a complex legal and operational status. Thus, the legality of Bittrex in the US is subject to these developments and the specific circumstances of its operations.