In 2018, he was sentenced to federal prison for unrelated securities fraud; a U.S. Attorney stated he "essentially ran his company like a Ponzi scheme". He spent five years in prison, and was released in May 2022.
Shkreli is also banned from the securities industry, and from serving as an officer or director of any publicly traded company.
If this was anyone other than Martin Shkreli, I might have been surprised to hear that, only a little over two months out of prison and while still staying in a halfway house, Shkreli is launching a "web3 drug discovery software platform".