Check out which companies are making headlines before the bell:
GameStop — The video game retailer reported adjusted quarterly profit of $2.40 per share. That beat estimates by 15 cents, with revenue essentially in line. However, the company's guidance for the current quarter and full year fell short of Street forecasts, as it tries to transition itself for a marketplace that sees an increased amount of activity moving online.
Hologic, Centene — The two stocks could benefit from an announcement that they are joining the S&P 500 index. Hologic, a maker of medical equipment, and Centene, a health insurer, will see their stocks join the index after the close of trading Tuesday. They'll replace energy services company Ensco, which moves to the S&P MidCap 400, and Pepco Holdings, which is being bought by rival utility Exelon.
Yahoo — Yahoo could be bought by a combination of Microsoft and private equity firms, according to Reuters, if talks between the company and those firms pan out. However, the discussions on currently being characterized as "preliminary."
Apple — Apple is expanding into original video content for its Apple TV product, with the first show an unscripted program about apps. No other details were provided by the company.
ADT — The security products company announced the expiration of the so-called "go shop" period, and will proceed with its planned acquisition by funds associated with Apollo Global Management. ADT said it solicited proposals from 24 potential acquirers, but no alternative transactions were proposed.
EMC — Privately-held computer maker Dell announced a deal to sell its information technology consulting unit to Japan's NTT Data for $3.05 billion. That will help it scale down some of the debt it will incur for its pending purchase of the data storage products company.
Qlik Technologies — The business analysis software maker is considering a potential sale, according to a Reuters report. Activist investment firm Elliott Management has been pushing for the company to considering strategic alternatives, after taking a nearly 9 percent stake.
Cal-Maine Foods — The egg producer reported third quarter profit of $1.33 per share, well above estimates of 99 cents, helped by higher average selling prices.
Acadia Pharmaceuticals — FDA staff members said Acadia's Parkinson's disease drug, Nuplazid, was effective in treating psychosis associated with the disease, and did not recommend a "black box" warning for the drug as has been the case with others used to treat that condition.
Berkshire Hathaway — UBS began coverage on Berkshire's class A shares with a "buy" rating and a price target of $244,500 per share. UBS said an uncertain market and economic environment plays to Berkshire's strengths, particularly strong cash generation and a portfolio of businesses that perform well.