RiskMetrics analysts have provided a last-minute fillip to Agrium's chances of vaulting to a place among the world's top-five listed fertilizer groups by recommending its hostile $4bn bid for CF Industries.

The corporate governance advisor said CF shareholders should accept Agrium's cash-and-shares offer, which expires on Monday.

"RiskMetrics clearly concurs that Agrium's offer provides a significant premium to CF's standalone stock price [and] is in-line with precedent deal valuations," Mike Wilson, the Agrium chief executive said.

Mr Wilson urged investors in his US-based target to "send an unambiguous message" to their board by tendering their stock to the offer, restating that unless a "compelling majority" of CF shareholders accept, Agrium will walk away.

Regulatory question

However, CF's directors, who have rejected the bid as too low, remained unmoved, noting a conclusion in the RiskMetrics report that its shares would be trading in the mid-$70s even without Agrium's overtures.

CF stock closed on Tuesday down $1.31 at $78.70 in New York.

And the US group cast doubt on Agrium's ability to win antitrust approval for a deal after it failed to resubmit documents needed to get the regulatory ball rolling.

Agrium said on May 26 it had withdrawn an initial regulatory filing to give the Federal Trade Commission more flexibility in timing its investigation.

Stephen Wilson, the CF chief executive, said: "Our board continues to be concerned with a number of risks associated with a potential combination with Agrium, including those related to value and timing of any transaction as a result of the ongoing regulatory review and potential remedies that may be required."

Fertilizer giant

CF added that it remained committed to its own plans to take over US rival Terra Industries, a deal Mr Wilson should be cleared by regulators "in the near term".

Agrium's New York-listed shares closed on Tuesday down $1.97 at $46.23, valuing its offer at $86.23 per CF share.