A California man has been charged with stealing $32 million from investors worldwide by promising returns from billion-dollar amber deposits, the Securities and Exchange Commission announced Thursday.

The SEC filed civil fraud charges and obtained asset freezes against Steve Chen and 13 California-based companies, including USFIA Inc., for perpetrating a worldwide pyramid scheme that falsely promised investors that they would profit from a venture purportedly backed by the company’s massive amber holdings.

USFIA and Chen’s other entities raised more than $32 million from investors in and outside the U.S. since at least April 2013 by promising a lucrative initial public offering for USFIA that never happened, according to the SEC complaint filed in federal court in Los Angeles. 

The SEC says Chen falsely promoted USFIA as a legitimate multilevel marketing company that owned several valuable amber mines in Argentina and the Dominican Republic. Investors were told that they could profit by investing in amounts ranging from $1,000 to $30,000, and that they would earn larger returns based on the number of investors they brought into the program.

The SEC also says Chen claimed to have converted investors’ holdings into “gemcoins,” which were described as virtual currency secured by the company’s amber holdings but which, in reality, are worthless, according to the SEC.

In addition to the asset freeze, the SEC is seeking the disgorgement of allegedly ill-gotten gains with prejudgment interest and civil penalties.