Tesla (TSLA, Financial) Motors will not acquire Nissan (NSANY, Financial), Elon Musk asserted in a Thursday post on social media platform X in response to speculation he could invest in the financially troubled Japanese automaker, which had been speculated to strike partnerships with Honda Motor and, or the Taiwanese tech manufacturer Hon Hai Precision Industry, commonly known as Foxconn.

Market watchers cited an earlier report from the Financial Times suggesting that Musk could buy Nissan's American assets. That news briefly lifted Nissan's stock price, but optimism petered out. Later on Thursday, Musk said he continued to focus on Tesla's Cybercab' robotaxi initiative and conceded he was not hunting for external acquisitions.

Nissan shares on the Tokyo Stock Exchange slumped about 10 percent after Musk made his comments, their steepest fall in three weeks. This is another downbeat sign on Nissan's balance sheet, which lacked a confirmed partner to revive the automaker's fortunes. Honda had tried to woo the company before, but to no avail, and it wanted to avoid ceding control to a direct competitor.

Conflict Watcher, a platform tracking global developments, said in a separate note that it would also add to dysfunction at Nissan if the automaker was not able to find strategic support to rebound from its slump as it faces mounting pressure to rebuild its image.