Shares in German giant K+S, the world's biggest salt miner, plunged 23 percent at open Monday, after Canadian rival PotashCorp scrapped its near eight-billion-euro ($9 billion) takeover bid.
The stock lost 23.21 percent to 23.81 euros at 0705 GMT.
In a statement published Sunday, the Canadian group said it was withdrawing its 41 euros per share offer, because of a "significant decline of global commodity and equity markets" as well as a lack of engagement by the German management.
K+S, which is also a leading world producer of potash for fertiliser, rejected PotashCorp's unsolicited 7.85 billion-euro takeover bid in July, and spurned a renewed bid at the same price in August, saying it was too cheap and "puts jobs at risk".
But PotashCorp chief Jochen Tilk said in a statement Sunday that the group's "proposal reflected full and fair value, and was predicated on a collaborative process with access to customary due diligence.
"Since that time, challenging macroeconomic conditions have contributed to a significant decline of global commodity and equity markets, with potash peer stocks down almost 40 percent," said Tilk.
"In light of these market conditions and a lack of engagement by K+S management, we have concluded that continued pursuit of a combination is no longer in the best interests of our shareholders," he added.
Potash, trapped in layers of salt, is the key ingredient in many fertilisers. It is a market believed to have enormous potential as the world tries to feed a growing population.
But the industry has been forced to adapt to a sharp fall in prices, sparked three years ago by the collapse of a de facto oligopoly, in which a few firms exerted control over the market.