new york sept 17 reuters  us stocks closed sharply lower in a broad selloff on friday ending a week buffeted by strong economic data corporate tax hike worries the delta covid variant and possible shifts in the us federal reserves timeline for tapering asset purchases all three major us stock indexes lost ground with the nasdaq composite index ixic suffering the biggest decline as rising us treasury yields pressured marketleading growth stocks they also posted weekly losses with the sp index spx suffering its biggest twoweek drop since february the market is struggling with prospects for tighter fiscal policy due to tax increases and tighter monetary policy due to fed tapering said david carter chief investment officer at lenox wealth advisors in new york equity markets also a little softer due to todays weak consumer sentiment data carter added its triggering concerns that the delta variant could slow economic growth a potential hike in corporate taxes could eat into earnings also weigh on markets with leading democrats seeking to raise the top tax rate on corporations to 265 from the current 21 while consumer sentiment steadied this month it remains depressed according to a university of michigan report as americans postpone purchases while inflation remains high read more inflation is likely to be a major issue next week when the federal open markets committee holds its twoday monetary policy meeting market participants will be watching closely for changes in nuance which could signal a shift in the feds tapering timeline it has been a week of mixed economic data and we are focused clearly on what will come out of the fed meeting next week said bill northey senior investment director at us bank wealth management in helena montana unofficially the dow jones industrial average dji fell 16815 points or 048 to 3458317 the sp 500 spx lost 4106 points or 092 to 443269 and the nasdaq composite ixic dropped 13796 points or 091 to 1504397 the sp 500 ended the session below its 50day moving average which in recent history has proven a rather sturdy support level of the 11 major sectors in the sp 500 materials splrcm and technology shares splrct had the biggest percentage drops shares of covid vaccine manufacturers pfizer inc pfen and moderna inc fell as us health officials moved the debate over booster doses to a panel of independent experts read more us steel corp dropped after it unveiled a 3 billion mill investment plan robinhood markets inc hoodo advanced following cathie woods ark invests purchase of 147 million worth of shares in the trading platform reporting by stephen culp additional reporting by krystal hu in new york and ambar warrick in bengaluru editing by richard chang