The two companies said that Honda sought to make Nissan a subsidiary. That shift angered Nissan’s board, a person familiar with the situation said.

The Japanese companies’ decision to call off negotiations highlights the challenges legacy automakers face in partnering to tackle new technologies.

Merger talks between Honda and Nissan have collapsed after the firms failed to agree on a multi-billion dollar tie-up deal. The Japanese car makers aimed to combine their businesses to fight back against competition from rival firms,