The 1994 Blissher fraud case has finally concluded after two company executives lost their appeals against combined jail terms of 120,945 years.
However, the law only allows a maximum punishment of 20 years imprisonment for this type of crime.
Blissher Inter Group Ltd swindled 24,189 people out of 826.27 million baht.
The company's staff intentionally deceived people into joining their timeshare business with the promise of free accommodation at leading hotels and resorts, according to a report in Thai Rath.
Angsunee Pattananithi, Saengthong Sae-Kim and Unnop Kunsawate were charged with conspiracy to commit fraud and sentenced to 120,945 years in prison on March 2008, five years imprisonment for each person they defrauded.
All three individuals appealed. Mr Unnop later dropped his case while Ms Angsunee and Mr Saengthong lost their appeal on Wednesday.
Blissher Inter Group Ltd, founded by Thana Atchariyawarodom, is a timeshare business mixed with the concept of multi-level direct sales.
Timesharing is a legal arrangement which permits the purchaser to own or use a home, apartment, condominium or resort for a set amount of time.
The firm allegedly advertised false promises of privilege, better living conditions and bright future prospects. The company's illicit business spread to remote villages and thus victimised many low-income earners.
The Finance Ministry intervened by freezing Blissher's bank accounts and pressed charges saying that the company's illegal activities would damage the nation's monetary system.
The 120,495 years sentences are the second longest jail terms handed out by a court in Thailand. in 1986, pyramid-scheme fraudster Chamoy Tipayasothe was sentenced to 150,000 years in prison.