The run-up of Netflix’s share price in recent months has Seaport Research Partners analyst David Joyce downgrading the stock to neutral from buy. In a research note, the analyst questions where else the stock price has to go after rapidly increasing to his $576 price target. “Whether Netflix is priced for perfection or not, we wonder who is the incremental buyer, and what are they playing for?” Joyce says. The big opportunity presented by Netflix’s new ad-supported subscription tier seems already baked into the stock price and has lifted valuation parameters far above normal ranges, the analyst says. Shares slip 1.9% to $564.81.