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.

TOKYO — Nissan is set to call off merger talks with rival Honda, a source said Wednesday, abandoning a $60 billion-plus tie-up that would have created the world's No. 3 automaker and raising questions about how it will drive a turnaround by itself.

Two of Japan’s largest automakers have been in talks to combine their operations to form one of the world’s biggest car groups.