While the offer represented a 16 percent premium to the prior day's close, PotashCorp. said the offer "substantially undervalues" the company and its prospects.
Potash Corp Chairman Dallas J. Howe said the BHP offer was "an opportunistic effort to transfer that value to its own shareholders."
The day following the takeover offer, share of PotashCorp. closed at $143 per share, on hopes that BHP will raise its offer to consummate a deal.