The United States Securities and Exchange Commission (SEC) is investigating whether Binance Holdings broke securities rules when it launched its BNB token in an initial coin offering (ICO) five years ago, Bloomberg reported on June 6.

Binance is the world’s largest crypto exchange, and BNB is the fifth largest cryptocurrency.

The BNB ICO took place in July 2017 on several platforms, during the height of the so-called ICO boom, and the Binance exchange opened just days afterward. According to Bloomberg, citing unnamed people familiar with the matter, at least one U.S. resident claimed to have taken part in the ICO, which could be a crucial fact for an SEC case, if the agency chose to pursue one. The SEC has claimed most cryptocurrencies are securities and brought cases against a number of ICO projects.

Binance founder and CEO Changpeng Zhao, often known as CZ, said in a 2020 blogpost that the wording of the BNB whitepaper was changed in January 2019 because “the potential for being misunderstood as a security is higher in certain regions.” Binance’s American arm, Binance.US, was created later that year.

Related: Binance wins dismissal of class action over 2018 tokens that tanked

Also on May 6, Reuters published a lengthy special report alleging that Binance processed at least $2.35 billion of transactions from hacks, investment frauds, and narcotics sales between 2017 and 2021, and had weak KYC/AML protections for those years.

Among other cases, Reuters mentions the hacking of Eterbase, with some of the proceeds being laundered through Binance by North Korean hacker group Lazarus, and Binance’s association with Russian-language drug mart Hydra.

A Binance spokesman disputed Reuters’ findings, and the exchange told Forbes in a statement that the report is a “woefully misinformed op-ed that uses outdated information from 2019 and unverified personal attestations.”

Binance is already the object of several U.S. federal investigations, include another SEC probe. The U.S. Commodity Futures Trading Commission (CFTC) began an investigation of the exchange’s trading practices last year.

Binance Markets, its United Kingdom branch, was ordered by the Financial Conduct Authority (FCA) to cease activities in that county after a review of its operations last year. Additionally, Binance was ordered to cease operations in Ontario last June, although it remained active in the Canadian province until March of this year.