Expansion of the nation's service sector slowed in December to weigh the markets down during the midday with the Dow slipping 13 points to 16,456. Nasdaq lost 13 points to 4118.

On the upside

The National Institute for Health and Care Excellence issued a positive Final Appraisal Determination for Cell Therapeutics' (Nasdaq: CTIC) non-Hodgkin lymphoma treatment Pixuvri.

Goldman Sachs upgraded SolarCity (Nasdaq: SCTY) from a Neutral rating to a Buy rating and lifted its price target from $65 to $80.

Pandora Media (NYSE: P) reported a 13% increase in December listener hours and a 13% increase in active listeners.

On the downside

Brightcove (Nasdaq: BCOV) will purchase Unicorn Media in a cash and stock deal valued at approximately $49 million.

Goldman Sachs downgraded First Solar (Nasdaq: FSLR) from a Buy rating to a Sell rating.

Best Buy (NYSE: BBY) stock dropped after rival electronics retailer Hhgregg forecast disappointing holiday quarter revenue that fell short of analyst expectations.

In the broad market, declining issues outpaced advancers by a margin of nearly 5 to 4 on the NYSE and by more than 5 to 3 on Nasdaq. The broader S&P 500 slipped 2 points to 1828. Bitcoin edged up $7.40 or 0.73% to $1009.50.