Federal prosecutors in Grand Rapids said they won't try to challenge the court's decision.
Michael Heshelman was four years into a 17-year sentence, while Bryce Sherwood was serving a five-year prison sentence.
The appeals court in April said the government took too long to bring Heshelman and Sherwood to court. The charges can't be refiled.
The unwitting investors included a Barry County pastor and his wife who lost $2.5 million. They created a foundation and had hoped to grow the money and spend it on charitable works.
The government accused Heshelman of living lavishly overseas with money from investors. He was extradited from Switzerland.