Check out which companies are making headlines before the bell:

Burger King Worldwide–Burger King has finalized its deal to acquire Canada-based doughnut chain Tim Hortons. Warren Buffett's Berkshire Hathaway will make a $3 billion investment in the form of preferred shares, and sources tell CNBC's Andrew Ross Sorkin that Buffett's investment will actually not save in taxes. Those sources say the structure of the deal is more about getting it approved by Canadian regulators.