Shale oil producer Pioneer Natural Resources Co PXD.N jumped 6.4% following a report that Exxon Mobil Corp XOM.N held preliminary talks with the company about a potential acquisition. By Stephen Culp NEW YORK, April 10 (Reuters) - The S&P 500 and the Nasdaq moved lower on Monday as investors digested Friday's employment report and prepared for an eventful week of inflation data and bank earnings. Recent indicators suggest a softening but sturdy economy, one that can withstand hawkish Fed policy as the central bank works to bring inflation closer to its 2% annual target.