Nike is starting to lose its dominant brand cachet in sports apparel, according to some on Wall Street.
Jefferies lowered its rating for Nike to hold from buy on Monday, citing lost sales to its surging competitor Adidas. The call helped send the stock down 3 percent in morning trading.
"The athletic footwear cycle and Nike brand power are strong, but the competitive landscape should make share gains and margin expansion elusive. … With expectations for less robust fundamentals, Nike's premium valuation conflicts with intensifying US competition unfolding," analyst Randal Konik wrote in a note to clients Monday. "Adidas has been successful in leveraging the spark from its fashion retro footwear resurgence into other categories like running and athletic apparel."
Nike underperformed the market the previous 12 months with its shares down 7 percent through Friday, compared with the S&P 500's 11 percent return. Its shares declined 4 percent on Friday after Foot Locker reported a disappointing second-quarter earnings report due to poor sneaker sales.
The analyst lowered his price target for Nike to $60 from $75, representing 9 percent upside from Friday's close.
Konik cited NPD data, which showed Nike lost 1.2 percentage points of market share in the year ending May 2017, compared with Adidas' 5 point share gain. He also said Adidas websites are rising in the traffic rankings, while Nike sites are falling, according to Alexa data.
"Web traffic depicts accelerating site visits for Adidas and slippage for Nike," he wrote.
The analyst said that mentions of Nike as the best-selling running brand declined to 59 percent this month from 66 percent in July, according to the firm's survey of sales associates.
"We believe secular industry tailwinds still exist, but Adidas brand heat dilutes them," he wrote. "Nike innovation is strong, but there's less buzz around its near-term pipeline."
Nike did not immediately respond to a request for comment for this story.
— CNBC's Michael Bloom contributed to this story.