Shares of Netflix Inc. NFLX, -1.91% sank 1.9% in afternoon trading Monday, after analyst Andy Hargreaves at KeyBanc Capital provided a caveat to his upbeat view on streaming video service’s long-term prospects that has kept him from being bullish the past 11 months. “While Netflix should remain the dominant global [streaming video-on-demand] provider, its 2019 results so far suggest increasing elasticity and/or a rising cost of customer acquisition, and the entrance of Disney as a direct competitor seems more likely than not to augment these trends,” Hargreaves wrote in a note to clients. “This suggests Netflix’s efficiency is unlikely to improve in the medium term, which reduces the potential for upside to expectations and neutralizes our view of the risk/reward.” Hargreaves reiterated the sector weight rating he’s had on Netflix since he downgraded it from overweight in October 2018. Netflix’s stock has gained 15.4% year to date, while Walt Disney Co. shares DIS, -0.80% have run up 37.2% and the Dow Jones Industrial Average DJIA, -0.73% has advanced 19.4%.