Buckingham Research Group lowered its rating for Netflix shares to neutral from buy, citing concerns over the company's spending on content to boost profit down the road.
"We are confident in Netflix's position as a global streaming leader with new entrants like Disney more apt to be complements than replacements," analyst Matthew Harrigan wrote in a note to clients Tuesday. "Nonetheless, continued share momentum depends on market confidence that NFLX's guided $3.0-4.0B in negative 2018 free cash flow will generate superior investment returns."
Netflix said it added 8.3 million subscribers in the fourth quarter compared with expectations for 6.4 million.
The shares rose 10 percent on Tuesday, closing at $250.29, giving it a market value of roughly $108 billion. Netflix stock is up 66 percent in the past 12-months through Monday.
Harrigan raised his price target for Netflix shares to $257 from $251, representing 13 percent upside to Monday's close.
The analyst noted the rising risks from Netflix's well-financed media and internet competitors.
"Even CEO Reed Hastings is open kimono that the global migration to IPTV content will attract new entrants and accelerating commitments from those currently engaged, which include deep pocketed tech companies like Amazon and companies with significant programming access like Hulu and European public broadcasters," he wrote.
Netflix stock downgrades are a rare occurrence on Wall Street in recent years. The last time the company was downgraded was in Sept. 2016, when Macquarie lowered its rating to underperform from neutral.
— CNBC's Patricia Martell contributed to this report.