Tuesday, December 11, 2012 09:52 AM EST - Bonterra Energy : has made an offer to acquire all of the issued and outstanding common shares of Spartan Oil, in which the shareholders of Spartan will receive 0.1169 of a common share of Bonterra for each Spartan share held. Based on Bonterra's December 10, closing price, this equated to $5.35 per Spartan share, a 20% premium to the Pinecrest Energy offer. Bonterra has also proposed to increase its dividend to 28 cents per share from 26 cents per month beginning in March 2013. Bonterra Energy ( T.BTE ) shares were up $0.04 at 45.07.