• by Joe Mandese  @mp_joemandese, January 25, 2016

The U.S. ad market finished 2015 with its highest December since MediaPost and Standard Media Index began tracking the marketplace in 2009. The U.S. Ad Market Tracker, a composite of actual ad spending processed by agencies representing 80% of the U.S. marketplace, hit a 238 in December -- its highest for the month, and its second-highest monthly total to date.

While the ad marketplace fell 25 points from an index of 263 in November, the decline follows normal cyclical patterns of ad demand that build going into the fourth quarter and erode coming out of the holiday shopping season. On a year-over-year basis, December rose 20 points over December 2014.

New data added to the index this month shows that the long-term expansion of the ad marketplace appears to be coming more from the biggest product categories. The top 10 categories turned in an index of 244 in December, six points over the overall marketplace and 28 points over the rest of the 11+ product category marketplace.

Across major media categories, digital continues to experience the most explosive expansion, and is the only sector in the index to gain in December vs. November 2015. Digital’s index rose to a record of 815 in December from a 728 in November. On a year-over-year basis, digital expanded 209 points.

The national TV marketplace was the only sector in the index to fall on a year-over-year basis, declining four points to a 162 in December 2015 from a 166 in December 2014.