The world’s largest crypto exchange Binance and the U.S. Securities and Exchange Commission (SEC) kicked off their oral arguments before a federal judge in Washington, D.C., yesterday, in a high-profile case that could help define how cryptocurrencies are regulated.

Binance has asked federal Judge Amy Berman Jackson to toss out a lawsuit the SEC filed alleging Binance broke its rules, and is expected to make its case for dismissal before her on Monday. The lawsuit is one of the last major legal challenges in the U.S. facing Binance.

Last year, Binance agreed to pay $4.3 billion to settle with the Department of Justice and the Commodity Futures Trading Commission over illicit finance breaches, founder Chanpeng Zhao pleaded guilty to breaking U.S. anti-money-laundering laws. But the SEC’s case is still hanging over the exchange.

Binance Holdings last year agreed to pay $4.3 billion to settle with the Department of Justice and Commodity Futures Trading Commission over illicit finance breaches, and Zhao pleaded guilty to breaking U.S. anti-money-laundering laws. But the SEC’s case is still hanging over the exchange.

The SEC in June accused Binance, Zhao and the exchange’s U.S. arm of artificially inflating its trading volumes, diverting customer funds, failing to restrict U.S. customers from its platform and misleading investors about its market surveillance controls.

The regulator also accused Binance of unlawfully facilitating trading of several crypto tokens the SEC deemed unregistered securities.

(Reporting by Chris Prentice; additional reporting by Hannah Lang and Jody Godoy;Editing by Alistair Bell)