Japan's biggest steel maker is top of the pile no more, as a resurgent yen hands a competitive advantage to overseas rivals amid an unprecedented global glut.

Nippon Steel & Sumitomo Metal Corp. has been overtaken as the world's most valuable producer by Europe's ArcelorMittal and is neck and neck with a revitalized Posco in South Korea for second place. In China, meanwhile, signs are emerging that the government is set to combine its biggest mills into two national champions, each far surpassing Nippon Steel in terms of output.

The biggest steel makers in Japan, including Nippon Steel and JFE Holdings Inc., will increasingly have to look for opportunities overseas as the population shrinks and the economy stagnates in a home market that they've long dominated. The yen's rapid appreciation has hurt them in export markets where they draw more than a third of their sales. JFE's Chief Executive Officer Eiji Hayashida has said the company needs to seek foreign deals to thrive beyond the construction boom planned for the 2020 Tokyo Olympics.