Activist hedge fund Elliott Investment Management disclosed a 5.04% stake in Nippon Express Holdings, prompting a sharp share rally.
Shares jumped up to 18% reaching 4,580 yen, ending the session 12% higher at 4,339 yen by 04:48 GMT.
The stake comes as Nippon Express pursues global expansion, recently agreeing to acquire Metro Supply Chain Group for about C$1.8 billion.