A 43-year-old Sioux Falls man is staring down 29 federal charges after prosecutors say he ran a textbook Ponzi scheme dressed up in crypto clothing, bilking investors out of an estimated $20 million over the better part of a decade.

Benjamin Paul Wiener, who operated a cluster of companies under the “Benaiah” brand, pleaded not guilty on July 10 and was released on bond. His trial is set for September 15.

The playbook: promise big, pay with other people’s money

The indictment, returned by a federal grand jury in June, paints a familiar picture. Wiener allegedly promised investors substantial returns on digital asset investments through entities like Benaiah Capital LLC and Benaiah Holdings Inc. In reality, prosecutors say, the money coming in from new investors was simply recycled to pay earlier ones.

Since at least 2018, Wiener’s Benaiah entities raised approximately $25.1 million, primarily from investors in South Dakota and Minnesota. Of that total, roughly $12 million was returned to investors. The other $13 million or so? Prosecutors allege $5.7 million went directly toward Wiener’s personal expenses.

The 29-count indictment includes wire fraud, money laundering, bank fraud, and aggravated identity theft. Each wire fraud and money laundering count carries a maximum sentence of 20 years in federal prison. The aggravated identity theft charges tack on a mandatory two years.

There’s also a separate bank fraud allegation. Prosecutors say Wiener obtained a $1 million line of credit in April 2025 using falsified documents.

How the scheme unraveled

A court-appointed receiver was assigned in August 2025 to investigate Wiener’s entities following investor complaints. The receiver’s investigation apparently gave federal prosecutors enough to bring the indictment roughly ten months later.

A key detail in the government’s case is the alleged laundering of proceeds through various banks and cryptocurrency exchanges. By routing funds through crypto exchanges, prosecutors allege Wiener attempted to obscure the trail of money flowing between investors and his personal accounts.

What this means for crypto investors

This wasn’t a scheme run out of a crypto-native hub. It was based in Sioux Falls, South Dakota, targeting investors in the Upper Midwest. South Dakota has recently passed regulatory measures specifically targeting digital currency scams, demonstrating increasing legislative focus on protecting investors from similar schemes.

Investors considering any digital asset fund or managed investment vehicle should verify registrations, demand audited financials, and be deeply suspicious of anyone promising consistent high returns in a market known for its volatility.