Alibaba did not respond to requests for comment.
Ma stepped down as Alibaba's chief executive in 2013, but remained executive chairman. Morley brought young Ma to Australia in 1985 for his first overseas trip, when he spent almost a month in Newcastle, an experience which the Chinese businessman said had "totally changed my future".
One of the world's richest men and a revered figure in his homeland of China, Mr Ma said it was "the beginning of an era, not the end".
Ma is part of a generation of billionaire entrepreneurs who made their fortunes as China embraced the digital age, creating some of the country's largest and most successful companies in the space of little more than a decade. Under President Xi Jinping, China's internet industry has grown and become more important, prompting the government to tighten its leash.
Huge conglomerates like Alibaba, Tencent, Baidu and JD.com are China's equivalent of western tech giants such as Amazon, Facebook and Google.
Ma also controls Ant Financial, the online financial platform that runs China's largest mobile payment system and money-market fund. The Chinese economy is also facing slowing growth and increasing debt, and the country is embroiled in an escalating trade war with the United States.
Liu was arrested and released without charge in the US city of Minneapolis last week. Numerous co-founders are still around, and professionals who joined the company later are now in charge.
Ma has long shown an admiration for Microsoft founder Bill Gates, who has donated vast amounts of his wealth to philanthropic causes.
"This is something I think I can do much better than being CEO of Alibaba", he told Bloomberg TV recently. The company owns or holds stakes in some of China's most important media assets, including the Twitter-like social media site Weibo and the Hong Kong-based English-language newspaper The South China Morning Post.
This year, regulators shot down a $1.2 billion bid for money transfer service Moneygram International Inc (MG.O) by Ant Financial on national security grounds, which the company said was related to "geopolitical" changes.
Speaking at an event in Australia in 2017, Ma explained his view on philanthropy.