Traders work on the floor of the New York Stock Exchange in New York City.

Check out which companies are making headlines before the bell:

Amazon, Berkshire Hathaway – The two companies and JPMorgan Chase have announced a partnership to explore ways to address health care concerns for their US employees. The stated goal of the partnership is improving employee satisfaction and reducing costs. The news has hit the shares of pharmacy benefit managers like Express Scripts, CVS Health, and UnitedHealth, as well as insurers and drug store operators.

Pfizer – The drugmaker reported adjusted quarterly profit of 62 cents per share, 6 cents a share above estimates. Revenue beat forecasts, as well. Pfizer also gave an upbeat 2018 forecast, and became the latest company to announce employee bonuses and increased investment stemming from the new tax law.

Aetna – The insurer earned an adjusted $1.25 per share for the fourth quarter, 5 cents a share above estimates. Revenue topped forecasts and Aetna, which is the process of being acquired by CVS Health, saw profit jump more than 75 percent compared to a year earlier.

Corning – The glass and fiber optic components maker beat estimates by 2 cents a share, with adjusted quarterly profit of 49 cents per share. Revenue also beat forecasts. The results were driven by strong demand for Corning's Gorilla Glass used in smartphones and other products.

PulteGroup – The home builder matched forecasts with adjusted quarterly profit of 85 cents per share, but revenue missed Street forecasts. The company reported a more than 12 percent increase in revenue, as it sold more homes at higher prices.

JPMorgan Chase – The bank announced that Chief Executive Officer Jamie Dimon will stay on for about five more years. The company also promoted executives Daniel Pinto and Gordon Smith as co-presidents and co-chief operating officers. Both have been mentioned as potential successors to Dimon.

Maxim Integrated – Maxim is in talks to be acquired by Japan-based chipmaker Renesas, according to sources who spoke to CNBC. A deal for the US chip company could be worth about $20 billion, although a deal is not imminent and may not happen.

MetLife – MetLife postponed its fourth-quarter earnings release and said it would revise some of its prior financial reports. The insurer took that action due to overdue monthly pension benefits, and said it planned to increase its reserves up to $575 million to cover the expense. MetLife also said the Securities and Exchange Commission has inquired about the pension matter.

Rambus – Rambus reported in-line quarterly earnings at an adjusted 19 cents per share. The chipmaker's revenue was slightly above forecasts, however Rambus gave a weaker-than-expected current-quarter outlook.

Revlon – The cosmetics maker's CEO Fabian Garcia is stepping down from that post in February. Board member Paul Meister will take over temporarily while Revlon searches for a new CEO. Garcia had joined Revlon from Colgate-Palmolive in 2016.

Tesla – Tesla engineer Ernest Villanueva left the company last year, according to a CNBC report. Villanueva helped design the batteries that power Tesla cars, and holds other patents as well.

Apple – Apple supplier Murata Manufacturing said a Monday report of a 50 percent production cut for the iPhone X appears to be overstated. The Japan-based company said it had not seen that large a drop in component orders from Apple.

Blue Apron, HelloFresh – HelloFresh, a key competitor for meal kit service, Blue Apron, said it is seeing a pickup in revenue growth. The German firm said it hoped to break even by the end of year and said sales had picked up in the U.S., its biggest market.

SAP – SAP saw 2017 results on the lower side of analysts' forecasts, after the business software company's CEO had forecast a "dynamite" fourth quarter for the company's cloud business. Separately, SAP announced the acquisition of cloud-based sales management software maker Callidus Software for $2.4 billion.

Blackstone – The private-equity firm is in talks to buy a roughly 55 percent stake in the financial and risk business of Thomson Reuters, according to a Reuters report quoting sources familiar with the matter.

Och-Ziff Capital Management – Och-Ziff director William Barr will depart the board, amid a battle for control of the hedge fund firm. An SEC filing said that Barr's decision stemmed from a disagreement over CEO succession.

Microsoft – Microsoft issued an emergency security update designed to disable an Intel patch. The patch had been designed to fix problems with one of Intel's chips, but caused computers to reboot an excessive number of times.

Wynn Resorts – The casino operator's stock remains on watch after representatives of CEO Steve Wynn met with Macau's gaming regulator over claims of sexual harassment. Wynn has denied the allegations.

Stein Mart – The discount retailer said it would explore strategic alternatives, given a challenging retail environment. Stein Mart said it would not provide any further updates until a transaction takes place or if the board determines such disclosure is appropriate.