Looking to build shareholder backing, Agrium (AGU) boosts the cash portion of its hostile bid for CF Industries (CF) by 10% - to $35/share from $31.70. Including stock, the offer values CF at $74.90 - 5.5% higher than Terra Industries' (TRA) rival bid of $72. CF +1.3% premarket. AGU -1.2%. TRA +0.1%.