The S&P 500 ended modestly lower, while a host of interest rate sensitive momentum stocks, many of which are slated to post third quarter-results this week, buoyed the tech-laded Nasdaq Composite Index to a higher close. "With nearly a third of the S&P reporting this week, investors are hoping these 'magnificent seven' companies will end up surprising to the upside," said Sam Stovall, chief investment strategist of CFRA Research in New York. Its wide-ranging Personal Consumption Expenditures (PCE) report, due on Friday, is expected to show annual headline and core inflation cooling down to 3.4% and 3.7%, respectively.