The company's Toronto-listed shares fell 3% in morning trade to C$50.74 following the deal, while they fell 2.8% to $38.44 on the NYSE.
"While the headline valuation is likely underwhelming, the deal shores up the balance sheet," said BMO Capital Markets analyst Ben Pham.
The valuation was "slightly below what we had previously embedded", analysts at RBC Capital Markets said.
Calgary, Alberta-based TC has previously disclosed plans to sell assets this year to reduce debt and fund its other projects such as the Coastal GasLink pipeline in British Columbia, which is grappling with major cost overruns.
TC was on course to deliver on its target to divest C$5 billion of assets by the end of 2023, CEO François Poirier said in April.
Columbia Gas and Columbia Gulf will be held in a new joint venture partnership and TC will remain the operator under the deal, which is expected to close in the fourth quarter.
TC and GIP will jointly invest in annual maintenance and modernization of the transmission systems, the company said, with GIP funding 40% share of gross capital expenditures, which are expected to average more than C$1.3 billion annually over the next three years.
The pipelines span more than 15,000 miles and deliver a substantial portion of daily U.S. natural gas demand, including about 20% of U.S. liquefied natural gas (LNG) export supply, according to TC Energy.
GIP currently manages $100 billion in assets, as per its website. Last month, the firm partnered with TotalEnergies and NextDecade to become a majority investor in Phase 1 of Rio Grande LNG Project.
($1 = 1.3180 Canadian dollars)
