Enbridge Inc. (NYSE: ENB), Canada's largest pipeline operator, said Aug. 24 it would buy its U.S. MLP Spectra Energy Partners (NYSE: SEP) for a sweetened deal of $3.3 billion.

Pipeline companies are reorganizing their business structure after the U.S. Federal Energy Regulatory Commission in March stopped them from claiming an income tax allowance as part of the fees they charge shippers.

"Significant weakening of the U.S. master limited partnership capital markets has adversely affected the growth opportunities for MLPs, including Spectra," Enbridge said in a statement.

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Enbridge raised its offer to 1.111 of its common shares for each Spectra unit, compared with its previous offer of 1.0123 of its shares.

Spectra Energy shares rose 5.7% to $40 in premarket trading, while those of Enbridge were marginally down.

BofA Merrill Lynch and Scotiabank are financial advisers to Enbridge. McCarthy Tetrault LLP, Sullivan & Cromwell LLP and Vinson & Elkins LLP are acting as the company's Canadian, U.S. legal and tax advisers, respectively.

Jefferies LLC is financial adviser to the Specta's conflicts committee, while Sidley Austin LLP is its legal adviser.

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