Canadian energy company Encana Oil & Gas expanded at the U.S. Bank Building at 950 17th St. in Denver. The energy company will now occupy an additional 46,241 square feet office space, bringing its total in the building to approximately 95,000 square feet comprised of the entire 22nd through 26th floors. About half of this space was already occupied by Alberta Energy Corp., a company that merged with Encana Oil & Gas. According to Joe Sigdestad of Fuller and Co., who represented the tenant, this transaction is especially significant as it marks an expansion by a downtown tenant, a fairly rare occurrence in today's economy. Doug Wulf, also of Fuller and Co., worked with Sigdestad to represent Encana. Nick Pavlakovich of Cushman & Wakefield of Colorado represented the landlord, The Carlyle Group.