California Developer Set to Plead Guilty in Massive $100 Million Real Estate Ponzi Scheme

California developer Ken Mattson faces up to 20 years in prison after agreeing to plead guilty to wire fraud in a 15-year real estate Ponzi scheme.

By: AXL Media

Published: Apr 15, 2026, 11:20 AM EDT

Source: Bisnow

Federal Prosecutors Detail a Decade of Deception

The long running legal battle involving Sonoma Valley developer Ken Mattson has reached a critical turning point as the defendant opted to change his plea. According to court reports, Mattson decided to plead guilty to at least one count of wire fraud after reviewing the extensive evidence compiled by federal authorities. The prosecution alleges that starting in 2009, Mattson orchestrated a sophisticated "classic Ponzi scheme" that systematically bilked investors out of more than $100 million. By falsifying records and moving assets between various shell companies, Mattson was allegedly able to mask significant financial shortfalls while maintaining the appearance of a successful real estate empire.

The Rise and Fall of the Mattson Portfolio

At the height of his career, Mattson controlled an expansive real estate footprint through his firms LeFever Mattson and KS Mattson Partners. His portfolio once included more than 200 commercial and residential properties across California, with an estimated valuation of $500 million. However, the integrity of these holdings collapsed under federal scrutiny, revealing that many properties were being used as leverage for unauthorized refinance payouts. Today, a significant portion of these assets sit vacant or in a state of decay, and both of Mattson’s primary business entities have since filed for bankruptcy protection.

Mechanics of the Multifamily Fund Fraud

A central pillar of the indictment involves a specific multifamily investment fund established in 2002. Prosecutors found that between 2019 and 2024, Mattson raised $24 million from at least 75 different investors under the guise of acquiring and managing apartment complexes. In reality, at least $10 million of that capital was diverted to cover management fees, pay off previous investors to maintain the illusion of profitability, and fund "off-book" personal transactions. The house of cards eventually folded when the developer could no longer secure enough fresh capital to satisfy the distribution demands of his existing investor base.