Stephen Curry #30 of the Golden State Warriors dribbles downcourt after stealing the ball from Mike Conley #11 of the Memphis Grizzlies.

Wall Street dunked on Nike's head Wednesday morning with Morgan Stanley and Bank of America Merrill Lynch downgrading the stock on concerns about weakening sales and rising competition.

"SportScan data shows Nike apparel sales trends have deteriorated significantly in 2016," Morgan Stanley's Jay Sole wrote in a note. "Adidas' U.S. resurgence is the biggest surprise and the most recent development — and this has changed the (Nike) thesis."