The Dow Jones Industrial Average (DJINDICES:^DJI) has lost 18 points in pre-market trading, suggesting a down start to the stock market today. World indexes crept toward all-time highs over the weekend, after the Dow and S&P 500 set their own records on Friday. Asian stocks notched a three-year high while European shares were unchanged as of 8:30 a.m EDT.

Meanwhile, news is breaking this morning on Family Dollar (UNKNOWN:FDO.DL) and Tyson Foods (NYSE:TSN) stocks, which should see heavy trading in today's session.

Family Dollar rallied higher by nearly 12% in pre-market trading after activist investor Carl Icahn announced that he has scooped up 9.4% of the discount retailer's outstanding shares. The disclosure that Icahn's company filed with the SEC doesn't give investors much in the way of details on the billionaire's plans, saying only that he intends to chat with management about "strategies to enhance shareholder value, which may include the pursuit of operating initiatives or the exploration of strategic alternatives." Family Dollar, for its part, said this morning in a press release simply that management is "open to dialogue with all shareholders." Investors appear to be betting that one the alternatives that Icahn could pursue would be a be a merger or buyout with rival Dollar General (NYSE: DG), whose shares also jumped 9.4% higher in early trading.

Tyson shares were down 1.4% in pre-market trading after the chicken giant today announced that it has boosted its bid for Hillshire Brands (UNKNOWN:HSH.DL) from $50 a share to $63. That increase brings Tyson's total potential cost up to $8.6 billion from the $6.8 billion that it originally offered last month. The new offer drove rival Pilgrim's Pride out of the hunt to acquire Hillshire, Reuters reported. Tyson investors are getting a valuable collection of food brands for that price. CEO Donnie Smith said in a press release that the purchase would be "a defining moment for Tyson Foods" in its "aspiration to be a leader in retail prepared foods, just as we are in chicken." The company said the expensive deal shouldn't jeopardize its credit rating, and would likely start to boost earnings in the first year after it closes.