The markets opened flat with the Dow adding 11 points to 16,936 after a record run last week. Nasdaq rose 7 points to 4,329.
On the upside
Jefferies upgraded Dollar General (NYSE: DG) from a Hold rating to a Buy rating.
Merck (NYSE: MRK) will pay a premium of approximately $3.85 billion in cash to acquire Idenix Pharmaceuticals (Nasdaq: IDIX).
Billionaire investor Carl Icahn acquired a 9.39% stake in Family Dollar Stores (NYSE: FDO).
On the downside
Profit taking weighed down shares of Keurig Green Mountain (Nasdaq: GMCR).
Shares of Melco Crown Entertainment (Nasdaq: MPEL) continued falling after FBR Capital warned on Friday of slowing growth in Macau.
Investors locked in profits on Halcon Resources (NYSE: HK).
In the broad market, advancing issues outpaced decliners by a margin of nearly 5 to 3 on the NYSE and by more than 5 to 3 on Nasdaq. The broader S&P 500 added a point to 1950. Bitcoin slipped $3.17 or 0.49% to $646.61.