The Dow Jones industrial average rose six points to 16,964 shortly after the market opened Monday. The Standard & Poor's 500 index eased three points to 1,976. The Nasdaq composite gained two points to 4,451.
Family Dollar soared 23 per cent after Dollar Tree announced plans to buy the rival discount store. Meanwhile, Trulia jumped 11 per cent after the real-estate listing service Zillow said it plans to buy it for $3.5 billion.
With one of trading week left in July, the stock market was on track for another month of solid gains.