TOKYO—Nissan Motor Co.’s former Chairman Carlos Ghosn’s chances of bail were derailed Friday when prosecutors cited new suspicions that he shifted personal losses to Nissan, in a move that keeps him behind bars longer.

Prosecutors said they suspected that in October 2008, in the midst of the global financial crisis, Mr. Ghosn temporarily forced Nissan to take over a personal derivative contract that was sitting on ¥1.85 billion ($16.6 million) in losses at the time.

Mr....