Japanese automaker Nissan (NSANY) finds itself at a crossroads. Nissan was poised to participate in a megamerger with rival Honda (HMC), and it was a huge development when the talks were revealed late last year.

Negotiations between Nissan and Honda are reportedly shaky after the two Japanese automakers previously announced they would merge by 2026.

A proposed $58 billion merger to create the world’s fourth-largest carmaker appears on the verge of collapse after Honda made an unexpected proposal to turn Nissan into a fully owned subsidiary, according to three people familiar with the matter.