Under the deal, Spectra unitholders will receive 1.111 Enbridge shares for each common unit. The proposal is up from an offer in May that Enbridge made of 1.0123 shares per unit.
Spectra Energy Partners is a master limited partnership and owns interests in pipeline and storage facilities for natural gas and crude oil.
Enbridge is the leading investor in the business, but the Houston-based company also has other investors.
Enbridge says the deal addresses changes caused by the loss of a U.S. tax allowance that will affect certain interstate pipelines held within master limited partnerships.
It also says the deal helps simplify and streamline its corporate structure.
Enbridge said it expects to issue about 91.0 million common shares in connection with the transaction, representing about a five per cent stake in the company.
The deal is expected to close in the fourth quarter of this year.
Companies in this story: (TSX:ENB)