SEATTLE — A Canadian company is the first marijuana business to complete an initial public offering on a major U.S. stock exchange, raising $153 million to expand its operations as Canada prepares to legalize the drug nationwide. British Columbia-based Tilray Inc.’s shares began trading Thursday on the Nasdaq stock exchange. Initially priced at $17, the stock quickly jumped, closing for the day at $22.55 – up about one-third. Tilray isn’t the first pot company to trade on a major American stock exchange, but it is the first to do so with an IPO, a step that could boost credibility and confidence in the industry, said John Kagia, an analyst with the marijuana market research firm New Frontier Data. “It’s another high-profile marker of how the cannabis industry is maturing and professionalizing,” he said. Two other Canadian marijuana companies began trading on major U.S.