Shoe maker Allbirds’ shares surged 90% in their market debut on Wednesday, as the company nabbed a valuation of roughly $4.1 billion. The company, known for its eco-friendly wool sneakers and slip-ons, opened its first trade at $21.21, after pricing 20.2 million shares a day earlier at $15 apiece, and raising roughly $303 million. Allbirds had marketed 19.2 million shares priced between $12 and $14, ahead of the initial public offering. Shares closed the day at $28.64 apiece, up nearly 91%. The company is now listed on the Nasdaq exchange under the ticker symbol “BIRD.” In going public, Allbirds is hoping to attract investors who favor companies that put an emphasis on sustainability. Read more at CNBC.