CALGARY -- Shares in AltaGas Ltd. are on the rise after it announced it has sold its U.S. transportation and storage business for $344 million to better focus on its core energy infrastructure operations and pay down debt. AltaGas announced the deal to sell the assets to an entity owned by Six One Commodities LLC and Vega Energy Partners, Ltd., after markets closed on Friday. On Monday, its shares rose by as much as 3.3 per cent or 71 cents to a new 52-week high of $22.28. In a report, analyst Nate Heywood of ATB Capital Markets says the deal is positive because it allows AltaGas to reduce leverage through the divestiture of non-core assets. The company says the sale includes a number of natural gas transportation and storage contracts, including about 31 billion cubic feet of leased and managed storage capacity. It produced US$21.2 million of normalized adjusted earnings in 2020 and posted a five-year annual average of US$16.2 million.