Albemarle Corp ALB.N ended lower after Goldman Sachs downgraded the lithium producer to "sell" from "neutral." Wall Street extended those gains as Fed Chair Jerome Powell during his news conference struck an upbeat tone about the U.S. economic recovery and expressed willingness to raise interest as necessary to control inflation. Wall Street remains down slightly this week after the S&P 500 index .SPX touched a record closing high on Friday, with worries about the new fast-spreading Omicron coronavirus variant giving investors pause.