Mining giant BHP Billiton has abandoned its takeover bid for fertiliser group Potash Corporation after it was blocked by the Canadian government.
BHP said it had been unable to convince the government of the deal's merits despite "unparalleled" pledges on jobs and investment.
Canada rejected the offer on 3 November, saying it was not convinced that it was in Canadian interests.
The Anglo-Australian mining giant had been given 30 days to appeal.
Saskatchewan-based Potash said BHP had "substantially undervalued" the group's potential.
BHP made a $38.6bn (£23.7bn) bid for the company in August.
"Unfortunately, despite having received all required anti-trust clearances for the offer, we have not been able to obtain clearance under the Investment Canada Act and have accordingly decided to withdraw the offer," BHP chief executive Marius Kloppers said.
In a statement, Potash said the bid "failed to reflect both the value of our premier position in a strategically vital industry and our future growth prospects".
BHP Billiton is the world's largest mining company, while Potash Corporation controls more than 25% of the world's supply of potash fertiliser.
Following BHP's abandonment of its bid, Canada's Industry Minister Tony Clement gave his first public comments on why the government had blocked the proposal.
"BHP did not demonstrate to my satisfaction that their plans to market potash would enhance Canada's already prosperous position to compete internationally," he said.
Mr Clement admitted Ottawa's move was controversial, adding that Canada still welcomed foreign investment.
Mr Kloppers has now seen three failed takeover or merger deals under his stewardship of BHP - after the firm's ill-fated attempt to buy rival Rio Tinto in 2008, and this year's abandonment of plans to form an iron ore joint venture with Rio.