CarMax official auto retailer of the NBA and WNBA. CarMax, Inc., the nation’s largest retailer of used cars, today announced a new partnership with the NBA, WNBA and Turner Sports. As part of the multiyear agreement, CarMax is now the official auto retailer of the NBA and WNBA – the first automotive retail partnership in WNBA history – as well as the presenting partner of NBA Tip-Off on TNT.