Stock futures swing positive shortly before the open, erasing early weakness after the stronger Markit flash PMI reading, which is in contrast to disappointing overseas PMI readings out overnight; S&P and Dow are now +0.1%, with the Nasdaq flat.
European and Asian markets were broadly lower after data showed Chinese manufacturing activity contracted further in February, and economic activity slowed in the euro zone.
Also, U.S. data showed jobless claims declined and retail inflation rose in line with expectations.
Facebook -1.4% premarket after announcing a $19B purchase of smartphone messaging company WhatsApp, Wal-Mart -1.8% after saying current quarter earnings would come in below analyst forecasts, and Tesla +11% after its Q4 beat estimates and providing an upbeat 2014 outlook.
Treasury are little changed, with the 10-year yield hovering at 2.74%.
Still ahead: Philly Fed, leading indicators, EIA natural gas and petroleum inventories.