Check out which companies are making headlines before the bell:
Spectra Energy — The Houston-based company is being bought by Canadian pipeline giant Enbridge in an all-stock deal worth $28 billion. The transaction creates the largest energy infrastructure company in North America.
Cepheid — The molecular diagnostics company is being bought by science and technology provider Danaher for $53 per share, or about $4 billion total including the assumption of debt. Danaher said Cepheid would add to earnings in the first year after the deal is complete.
Herbalife — Investor Carl Icahn bought nearly 307,000 more shares on August 31, according to a Securities and Exchange Commission filing, and now holds about 19.6 million shares in the maker of nutritional supplements.
Monsanto — Germany's Bayer raised its bid for Monsanto to $127.50 per share, up from its prior $125 per share. The agricultural chemical and seeds company said it was having "constructive" discussions with Bayer about a possible deal.
General Motors — The automaker settled the last two of so-called "bellwether" cases over its ignition switch issue. The faulty switches were linked to 124 deaths and 275 injuries.
Liberty Media — Liberty Media is close to a deal to buy a 10 percent to 15 percent stake in racing car series company Formula One, according to the Financial Times. The paper said a final deal is expected to be announced within the next two weeks.
General Electric — GE announced deals to acquire two European 3-D printing firms for a total of $1.4 billion. GE's deals appear to have spurred interest on other 3-D printing stocks such as 3D Systems and Stratasys, which are moving higher in premarket trading.
Intel — Intel was upgraded to "buy" from "hold" at Evercore, which notes the chipmaker's underperformance compared to other semiconductor stocks and potential catalysts to improve its financial results.
Urban Outfitters — Urban Outfitters was added to the "Franchise Picks" list at Jefferies, which said the apparel retailer appears to be ahead of the curve on several trends in the industry including a "retro" trend popularizing fashions from the '90s.
Gilead Sciences — The drugmaker was upgraded to " buy" from "hold" at Jefferies, citing confidence in the prospects for Gilead's HIV treatments among other factors.
Goodyear Tire — Deutsche Bank upgraded the tire maker's shares to "buy" from "hold," citing earnings growth prospects and increased cash payouts to shareholders, among other factors.
PayPal — The payment services company struck a deal with MasterCard, allowing users to set MasterCard credit or debit cards as a default payment method. In return, MasterCard is dropping a fee that it had been charging PayPal, which has a similar deal in place with Visa.
Lockheed Martin — Citi resumed coverage on the defense contractor with a "buy" rating, saying it likes defense stocks in general and most favors ones with revenue and margin expansion on the horizon.
Mondelez International — JPMorgan Chase rates the snacks maker "overweight," pointing both to the potential as a takeover play as well as a cost savings plan that is running ahead of schedule.