The Dow Jones U.S. Media Index was down 3.5% today while the DJ Industrial Average was off 2.4% — and Goldman Sachs may have contributed to the imbalance: It downgraded the entertainment sector today to “neutral” from “attractive” saying that ad sales will be weaker than expected as the overall economy softens. That came as the market also reacted to Greece’s report over the weekend that it will fail to hit its deficit-reduction targets for the year — increasing the possibility of a default. CBS, -7%, was the biggest loser among the major media companies. It was followed by Viacom (-5.1%), Sony (-4.7%), Disney (-3.9%), Time Warner (-3.4%), and Comcast (-2.2%). In the broader media market, broadcasters Westwood One, LIN TV, Rado One, and Entercom were down by more than 10%. Pandora, Live Nation, Crown Media and Cumulus Media lost more than 8% of their market value. A few companies were up for the day including Yahoo (+2.7%), Regal Entertainment (+2.0%), Coinstar (+1.6%) and Time Warner Cable (+0.2%).