Shares of Wayfair Inc. /zigman2/quotes/201071690/composite W +1.60% sank 8.0% in afternoon trading Friday, after BofA Securities analyst Justin Post downgraded the home furnishings online retailer, citing evidence of a deceleration in sales trends. The stock, which has pared earlier intraday loss of a much as 14.9%, has still shed 25.9% since closing at a record $342.40 on Aug. 26. Post cut his rating to neutral, after being at buy since April 7. He kept his stock price target at $330, which is 30.1% above current levels. "Expectations and valuation are high vs. history, and we expect revenue deceleration ahead, which has been a historical valuation headwind for the stock," Post wrote in a note to clients. "We think [quarter-to-date] stock appreciation has been fueled by expectations for upside, but given recent data points, we see less upside to Street estimates for 58% growth in 3Q." The stock has gained 28.4% so far this quarter, compared with a 20.5% rise in the Amplify Online Retail ETF /zigman2/quotes/206522380/composite IBUY +4.43% over the same time and the S&P 500's /zigman2/quotes/210599714/realtime SPX +1.49% 9.4% advance.