On September 27, Binance founder and former CEO Changpeng “CZ” Zhao was released from a U.S. federal prison after serving a four-month sentence for violating anti-money laundering (AML) rules, a spokesperson for the U.S. Federal Bureau of Prisons told Bitcoin News.

CZ pleaded guilty in November to federal charges of failing to implement proper AML controls at Binance, the world's largest cryptocurrency exchange by daily trading volume, according to a Nov. 21 statement from the U.S. Department of Justice. He also resigned as CEO of Binance.

With a reported net worth of around $60 billion, CZ is the richest person ever to serve a prison sentence in the United States.

In April, CZ agreed to return to the United States from Dubai to serve a four-month sentence. He spent the first two months in a minimum-security prison in Southern California, then moved to a resettlement home in Long Beach, where he was allowed out under supervision during the day, Fortune reported on September 26.

“We are excited that CZ will be going home to his family,” a Binance spokesperson told Crypto Blog, adding:

“While he will no longer be managing or operating Binance, we are excited to see what he does next. Since last year, Binance has continued to grow strongly under the leadership of the current team, surpassing 230 million users globally.”

CZ's four-month sentence is a significant reduction from the 36 months the Justice Department originally requested to “reflect the seriousness of the offense.”

According to an official statement from the US Department of Justice, CZ's guilty plea not only covers violations of AML regulations but also involves unlicensed money transmission and sanctions violations.

“Zhao knew that his decision to fail to implement an effective AML program would result in Binance facilitating transactions between U.S. users and users in Iran and other prohibited countries and regions, in violation of U.S. law,” prosecutors wrote in the sentencing memo.

During a hearing on April 30, Seattle District Judge Richard Jones explained his four-month sentence decision by saying there was no evidence that CZ was informed of any illegal activity at Binance.

CZ agreed to pay a $50 million fine as part of a U.S. settlement last November, and Binance has also paid a total of $4.3 billion in fines for violating U.S. AML laws. However, CZ’s personal assets were not affected by the settlement.

Binance founder still retains the largest stake in Binance, reportedly owning around 90% of the exchange.