• U.S. prosecutors sought to tighten the bond conditions of billionaire Binance founder Changpeng "CZ" Zhao before he is sentenced for breaking a federal anti-money laundering law.
• The new bond conditions would order Zhao to surrender his Canadian passport, and provide prosecutors with at least three days' notice before he travels within the country.

U.S. prosecutors Friday asked a judge to tighten the bond conditions of billionaire Binance founder Changpeng "CZ" Zhao as he awaits his April sentencing for breaking a federal anti-money laundering law, court filings show.

Zhao pleaded guilty in late November to a charge of failure to maintain an effective anti-money laundering program in violation of the Bank Secrecy Act, and stepped down as Binance's CEO at the same time.

Under the proposed bond, Zhao would be required to provide prosecutors and pretrial services with at least three days' notice before any travel within the country, to give them time to raise any potential objections.

The new bond conditions would also order Zhao to surrender his current Canadian passport, and they would bar him from applying for a new one without the court's permission. He would also be barred from changing his place of residence without prior approval.

Zhao's lawyers objected to the proposal, according to the filing. An attorney for Zhao did not immediately respond to CNBC's request for comment.

Judge Richard Jones barred Zhao from traveling outside the United States in mid-December, after determining that Zhao's "enormous wealth" and lack of U.S. ties created a risk that he might flee if allowed to return to his home in the United Arab Emirates.

The prosecutors' latest filing in U.S. District Court in Seattle noted that pretrial services officers have recommended further restricting Zhao's movement, allowing him to travel only to the western district of Washington and the district where he currently resides.

Pretrial Services also recommended "a location-monitoring condition," the filing said in a footnote. The filing does not explicitly ask the judge to impose that condition.

Zhao, a Canadian national, is free in the U.S. on a $175 million personal recognizance bond. His attorneys have argued that he has taken responsibility for his actions, noting that he is paying a personal penalty of $150 million to the U.S. Commodity Futures Trading Commission as part of his agreement with the government.

The Department of Justice announced Zhao's guilty plea in tandem with an agreement by Binance to pay more than $4.3 billion to resolve multiple federal charges. Attorney General Merrick Garland at the time called it "one of the largest corporate penalties in U.S. history."

Federal sentencing guidelines suggest Zhao could face up to 18 months in prison. Prosecutors have reportedly considered asking for a harsher sentence.

A Dec. 22 letter to the court, made public with redactions in late January, revealed that Zhao had asked to return to the UAE for up to four weeks to attend to someone in his life who was scheduled to undergo surgery.

Zhao offered to pledge all of his equity in Binance US in order to assuage concerns about his potential risk of flight, the letter showed. That equity was worth $4.5 billion as of the company's most recent round of fundraising two years earlier, Zhao's lawyers said in the letter.

Jones denied the travel request on Dec. 29.