Enbridge Inc. ENB, -1.44% and Spectra Energy Corp. SE, +2.13% announced Tuesday that they have agreed to merge to create the largest energy infrastructure company in North America. The two companies will combine in a stock-for-stock merger transaction, which would value Spectra Energy's common stock at $28 billion, and give the overall company a pro-forma enterprise value of about $127 billion. The transaction was approved by both boards and is expected to close in the first quarter of 2017 at which time the company will be called Enbridge Inc. Spectra Energy shareholders will receive 0.984 shares of the merged company for every share of Spectra they own and the existing Spectra shares are valued $40.33 a share. Shares of Spectra Energy were up 6% in pre-market trade.