Check out which companies are making headlines before the bell:

General Motors — In a roundup of auto companies, Piper Jaffray wrote in a note that General Motors is "very cheap" compared to others in the industry. The firm views GM as "the second least-risky" company in its coverage and named the motor city giant as one of its top picks.

Nike — Guggenheim raised its outlook on Nike ahead of the company's second quarter earnings later in December, saying in a note the athletic brand offers an "attractive" balance of risk to reward for investors.

Alexion Pharmaceuticals — Biopharma analysts at Leerink Partners answered investors' calls for an outlook on Alexion's drug ALXN1210, which is being evaluated for the treatment of patients with paroxysmal nocturnal hemoglobinuria. Leerink wrote in a note it sees Alexion shares rising 30 percent in a base outcome from Phase 3 trials for the drug.

Trivago — Deutsche Bank raised its rating on the travel services company to "buy" from "hold," saying in a note Trivago should benefit from a stabilizing bidding environment among its more substantial customers.

TE Connectivity — The board of TE Connectivity announced it was repurchasing $1.5 billion in company shares and raised the company's quarterly dividend to 44 cents per share from 40 cents per share.

Transocean — The offshore drilling contractor announced that wealth advisory firm Wilmington Trust filed a lawsuit against Transocean-subsidiary Global Marine, alleging the company is in default of $300 million. Transocean said it intends to "vigorously defend" the suit.