U.S. equities notched their biggest weekly decline since mid-June in volatile trading as investors assessed the latest read on the economy after more strategists weighed in with cautious comments on the market. The S&P 500 fell 0.8%, pushing its loss for the holiday shortened week to 1.7%. Markets have been volatile as the continued spread of Covid-19 has undermined the economic recovery and lifted supply-shock inflation, even as central banks reaffirm an accommodative stance.