Levi Strauss & Company, the denim company that traces its roots to the days of the California Gold Rush, started trading publicly on Thursday for the second time in its 165-year history.

The company’s shares were priced at $ 17 each, giving it a valuation of roughly $ 6.6 billion. The stock opened at $ 22.22 and jumped in trading by noon in New York, where the stock exchange suspended its prohibition on wearing jeans for the day.

Levi’s, which sells jeans and Dockers, has been undergoing a turnaround for the better part of the past decade under its chief executive, Charles V. Bergh, who joined the company in 2011. While the San Francisco company has yet to return to its peak of the 1990s, Mr. Bergh has overseen an increase in sales to $ 5.6 billion last year, with net profit of $ 285 million.

[Being publicly traded is the latest chapter in the story of the 165-year-old company.]

The company was founded by Levi Strauss, who immigrated to the United States from Bavaria and set up shop in San Francisco in 1853 with a wholesale dry goods business. Twenty years later, he and a business partner received a patent for “waist overalls” with metal rivets at points of strain — a garment known today as the blue jean.

The company first listed its shares in the 1970s, but was taken private in 1985 through a leveraged buyout led by descendants of Strauss, known as the Haas family. They wanted to take a longer-term view of the business rather than focus on short-term results and fluctuations. Strauss died without children in 1902 and left the company to his nephews. Family members have controlled the business ever since.

Levi’s will raise more than $ 100 million from the offering, which it plans to use for general corporate purposes and possibly acquisitions, according to its regulatory filings. Much of the offering’s proceeds will go to the Haas family.

Members of the Haas family, known for their donations to the University of California, Berkeley, where the business school carries the family name, will hold about 80 percent of the voting shares after the offering.