Sioux Falls Investor Indicted in $20M Crypto Fraud

A federal grand jury returned a 29-count indictment last month against Benjamin Paul Wiener, 43, of Sioux Falls. The charges include wire fraud, money laundering, bank fraud and aggravated identity theft, U.S. Attorney Ron Parsons announced Thursday.

Wiener appeared before U.S. Magistrate Judge Veronica L. Duffy on July 10 and pleaded not guilty. He was released on bond and is scheduled to stand trial Sept. 15. Prosecutors say the alleged scheme affected dozens of investors in South Dakota and Minnesota and led to estimated losses of about $20 million.

According to the indictment, Wiener solicited investments for several companies he controlled and used materially false statements to persuade people to transfer cash and cryptocurrency. After receiving investor funds, he allegedly routed the money through banks and cryptocurrency exchanges to mask its origin, ownership and control, and then spent the proceeds on personal expenses.

When investor funds ran low or clients requested returns, the filing says Wiener recruited new investors and used their money to pay earlier investors, a pattern described in the indictment as consistent with a Ponzi scheme. The document names eight entities, including multiple limited liability companies, that prosecutors say served as vehicles for the transfers.

One bank fraud count centers on a Sioux Falls financial institution. The indictment alleges that in April 2025 Wiener obtained a $1 million line of credit by falsifying documents and correspondence and by using another person’s identifying information without authorization.

The 29-count indictment includes wire fraud, money laundering, bank fraud and aggravated identity theft. Wire fraud and money laundering each carry up to 20 years in prison; bank fraud carries a maximum of 30 years. Aggravated identity theft carries a mandatory minimum two-year term that must run consecutively to any other sentence imposed.

The U.S. Attorney’s Office is handling the investigation with assistance from IRS Criminal Investigation and the FBI. Federal prosecutors have increased actions targeting alleged crypto-related fraud in recent years, with several high-value cases brought in multiple jurisdictions.