Seven & i, Nissan Deal Fallout Leaves Japan Companies Vulnerable

It seemed like an extraordinary display of patriotism and unity: Japan’s biggest companies would come together to save their own, whether ailing carmaker Nissan Motor Co. or besieged convenience store giant Seven & i Holdings Co.

Roughly six months later, ambitious plans to merge Nissan with Honda Motor Co. and take the operator of 7-Eleven convenience stores private have both fallen apart, leaving them grasping for solutions and potentially even more vulnerable to foreign takeovers.

The failure to find a fix that would keep two of the country’s most famous brands under Japanese control marks an unprecedented opening in ...