NEW YORK— The S&P 500 ended slightly down on Thursday, paring losses in late trading after unexpectedly strong retail sales data underscored the strength of the U.S. economic recovery. The three major indexes spent much of the day in negative territory as rising U.S. Treasury yields pressured market-leading tech stocks, and the rising dollar weighed on exporters. Amazon.com Inc., buoyed by solid online sales in the Commerce Department’s report, helped push the Nasdaq into positive territory. “Looking at today, clearly we had positive news from retail sales and it looks as if the massive slowdown in the economy is not materializing as a lot of people expected,” said Ryan Detrick, senior market strategist at LPL Financial in Charlotte, North Carolina. “It’s a nice reminder that the economy is still taking two steps forward for each step back even amid the COVID concerns,” Detrick added. Economically sensitive transports and microchips were among …