Remember the mayhem that the adidas NMD caused on its global launch day in March? That buzz paid off big for adidas, which sold more than 400,000 pairs of the sneaker on its launch day.

Herbert Hainer, CEO of adidas-Group, mentioned the massive figure while discussing the Three Stripes' recent successes in its first-quarter 2016 earnings report. Hainer called the NMD the hottest shoe in the game and gave two specific reasons for its buzz.

"On the one hand, it is of course the unique look and feel as NMD is technically a running shoe realized as a lifestyle sneaker," he explained. "Its midsole is elevated with adidas Boost technology, while the upper utilizes the integrity of adidas Primeknit. This offers highest comfort, combined with cutting-edge design. On the other hand, the success of NMD also goes back to a number of special activations, including launch events and campaigns that took place in key cities around the world."

Despite so many pairs being out in the wild, many NMDs are still doing well on the resell market. The Primeknit pairs, for example, sell for upwards of $500.