“When they enter international markets, they use a test-and-learn model,” says Danielle McCoy, an analyst at Brean Capital in New York, noting that the company usually teams up with a well-established partner and expands only after demand has been proven. L Brands and Dufry, the duty-free concessionaire that will operate the Victoria’s Secret store in São Paulo, declined to comment, as did Bündchen’s twin sister, Patricia, who acts as her spokeswoman in Brazil.