That figure compares to an appraised value of $295 billion as at the end of August. Fidelity was among a small group of global investors that bought into Ant three years ago.
Ant's initial public offering was canceled in spectacular fashion last November and Chinese regulators later ordered the enterprise to convert into a financial holding company, denting Ant's appeal in the eyes of investors.
The central-government investigation, which started early this year, focuses on "regulators who greenlighted the initial public offering, local officials who advocated it and big state firms that stood to gain from it", according to the report.
Ma's relationships with these "state stalwarts" are also being examined as part of the investigation, the report said.
The Wall Street Journal previously reported that Ma had offered in a November meeting with regulators to hand over parts of Ant to the Chinese government.
Ant denied that a divestment of Ma's stake was ever under consideration. "Divestment of Mr. Ma's stake in Ant Group has never been the subject of discussions with anyone," an Ant spokesman said in a statement.
Last year, Chinese premier Xi Jinping blocked Ant Group's initial public offering, as it was speculated that the decision was based on Jack Ma's public criticism of Jinping's financial oversight campaign, and that it could add risk to the financial system.
A group of well-connected Chinese power players backed the company; including those linked with political families that pose a potential challenge to Jinping's authority.
Investors largely shrugged off comments by US President Donald Trump that a nearly $900 billion stimulus bill, agreed upon after months of wrangling in Congress, was "a disgrace" that he might not sign.
China blocked the fintech giant's $37 billion listing on Tuesday, thwarting its debut in Hong Kong and Shanghai scheduled for Thursday and dealing a severe blow to the company founded by billionaire and Alibaba co-founder Jack Ma.
The entry of large tech firms into finance has led to concerns about fair competition and data privacy as well as other issues, the China Securities Journal quoted Zhang Zixue, a professor at the China University of Political Science and Law, as saying.
The shift in strategy by the Alibaba-backed fintech giant came late in 2019, brought on by a change at the helm and a reworking of priorities as it planned for its IPO and grappled with regulatory challenges at home.