NEW YORK (AP) — Stocks closed slightly lower on Friday in a quiet day of trading as investors returned from the Christmas holiday. The SP 500 index fell 2.11 points, less than 0.1%, to close at 6,929.94, the Dow Jones Industrial Average fell 20.19 points, also less than 0.1%, to 48,710.97 and the Nasdaq composite [...] ...read more read less