The court ruled that no sufficient evidence was found to support the case of the plaintiffs against the co-defendants.
It issued its verdict on Monday. The written version of the court ruling was released yesterday.
NMG owns The Nation newspaper.
The lawsuit was filed by public prosecutors and Prathum Ruangsud, who claimed to represent 31 NMG shareholders holding 402.5 million shares in the company.
The nine defendants were former NMG chairman Nittimon Hastindra na Ayudhya, board members Suthichai Yoon, Pakorn Borimasporn, Chaveng Chariyapisuthi, Adisak Limprungpatanakit, Kaemakorn Vachiravarakarn, Pana Janviroj, Duangkamol Chotana and Sermsin Samalapa.