US jury indicts South Dakota crypto investor on 29 counts over alleged $20 million investor fraud

Quick Take

• A federal grand jury indicted Sioux Falls resident Benjamin Paul Wiener on 29 counts tied to an alleged $20 million fraud scheme that drew in dozens of victims across South Dakota and Minnesota.
• Prosecutors allege Wiener ran a Ponzi-style operation through eight entities, paying earlier investors with new money while routing funds through banks and crypto exchanges to bankroll personal spending.

A federal grand jury indicted Sioux Falls crypto investor Benjamin Paul Wiener on 29 counts of wire fraud, money laundering, bank fraud, and aggravated identity theft, U.S. Attorney Ron Parsons announced Thursday.

Wiener, 43, appeared before U.S. Magistrate Judge Veronica L. Duffy on July 10 and pleaded not guilty. He was indicted last month and released on bond pending a Sept. 15 trial.

Prosecutors allege Wiener made materially false statements to induce victims to hand over money and digital currency to his companies. The scheme hit dozens of victims across South Dakota and Minnesota, with estimated total losses of approximately $20 million, according to the indictment.

After collecting the funds, Wiener allegedly moved them through financial institutions and cryptocurrency exchanges to obscure their source, ownership, and control, then spent them on personal expenses.

When investor money ran dry, or a client asked for their capital back, Wiener allegedly recruited new investors and used the fresh funds to repay earlier ones — the mechanics of a Ponzi scheme. He reportedly used eight entities, including several LLCs, as vehicles for the fraud.

The bank fraud count centers on a Sioux Falls financial institution. In April 2025, Wiener allegedly secured a $1 million line of credit by falsifying documents and correspondence and using another person's identifying information without authorization.

Wire fraud and money laundering each carry up to 20 years' imprisonment. Bank fraud carries a maximum sentence of 30 years. Aggravated identity theft carries a mandatory minimum two-year term that runs consecutively to any other sentence. The IRS Criminal Investigation unit and the FBI are handling the investigation alongside the U.S. Attorney's Office.

The case lands amid a run of federal crypto fraud prosecutions.

A New England man was charged in February over an alleged scheme in which he posed as a successful crypto investor and lost nearly $1 million of victim funds on the offshore gambling site Stake.com.

In June, a Washington man was sentenced to five years for helping launder nearly $100 million in proceeds from overseas scams through dozens of bank and exchange accounts.