Check out which companies are making headlines before the bell:
Norfolk Southern — Canadian Pacific Railway has ended its effort to strike a merger deal with Norfolk Southern, saying it sees no clear path to a transaction in light of Norfolk Southern's resistance.
Yahoo — London's Daily Mail is the latest party interested in participating in a bid for Yahoo's assets, although the paper said talks with several potential bidders are at an early stage and there's no guarantee a deal will be done.
Hatteras Financial — The mortgage real estate investment trust will be bought by rival Annaly Capital Management for $1.5 billion in cash and stock, or $15.85 per share. That compares to the Friday close for Hatteras of $14.26 per share.
Alphabet — Pivotal Research Group upgraded the stock to "buy" from "hold" on optimism about upcoming earnings and diminishing negative impact from foreign exchange.
Overstock.com — Founder and CEO Patrick Byrne is taking a medical leave of absence as he undergoes treatment for hepatitis C. Byrne said he does not know if he will return, and has recommended that the board appoint general counsel Mitch Edwards as acting CEO.
Bloomin' Brands — Credit Suisse upgraded the Outback Steakhouse parent's shares to "outperform" from "neutral," saying despite weakening sales and a lower market share, the challenges facing the company are understood and already priced into the stock.
Restaurant Brands International — RBC upgraded the parent of the Burger King and Tim Hortons chains to "outperform" from "sector perform," noting sales momentum at Burger King and fewer headwinds from foreign currency.
United Continental — The airline is forecasting a decline of up to 7.75 percent in its revenue per available passenger seat mile, hurt by a strong dollar and a decline in travel by customers whose businesses are impacted by lower oil prices.
General Motors — A fourth case involving defective ignition switches was dismissed. According to a GM spokesman, there was no settlement in the case involving the switches. This trial had been scheduled to start in July.
SAP — SAP said first quarter results for the business software maker would be weaker than expected, on a slower pace of sales of software licenses to corporate customers.
General Electric — GE is planning an initial public offering for its Czech banking business, according to the Financial Times. The FT said GE would retain a significant minority stake in the unit.
Seagate Technology — Seagate got a positive mention in Barron's, which said the hard disk drive maker's 7.6 percent yield is enticing and that it would benefit from increased demand for large drives used in data centers.
McDonald's — The restaurant chain has put its Korean unit up for sale and hired Morgan Stanley to seek out potential buyers, according to a Korean newspaper.
Toll Brothers — Toll could climb to $40 per share or more from Friday's close near $29, according to Barron's, which points to the home builder's successful expansion into the New York City luxury condominium market.