The manufacturing index fell to 49.5 in November from 51.2 in October, raising concerns about the economy and whether the Federal Reserve will cut interest rates at its Dec. 12 meeting. The Dow dropped 27.80 to close at 12,194.31, down nearly 1 percent for the week. The Nasdaq fell 18.56 to 2,413.21, nearly 2 percent for the week. Omnicom shares rose about half a percentage point to 103.21. WPP shares were up almost 2 percent, closing at 66.16, and Publicis saw an uptick of just over 2 percent, closing at 38.80. IPG shares were essentially unchanged with a Friday close of 11.95.