Fortune Article

Meg Whitman -- HP

Whitman has moved the company forward since taking over in October 2012 -- relatively speaking. The 3% dip in sales, to $29.1 billion, in the company's fiscal year fourth quarter was its smallest decline in nine quarters. But it's still unclear if the changes Whitman has implemented, like reducing the size of HP's (HPQ) product line, will lead the company to revenue growth.

Marissa Mayer -- Yahoo

Though Mayer won Wall Street's favor with stock buybacks and big-name acquisitions -- like Tumblr and Summly -- soon after joining Yahoo in July 2012, the buzz over Yahoo hasn't been reflected in its revenue, which increased by only 2% in her first calendar year as CEO. The gains Yahoo's (YHOO) stock has made of late are mostly a result of its investments in Alibaba and Yahoo Japan, not the success of its core business.

Tim Armstrong -- AOL

Armstrong's decision to suddenly fire a Patch employee during a companywide meeting was his most notable contribution of 2013. In 2014, he hopes his investment in what he calls a "megatrend" -- the automation of advertising -- will serve him better and give a jolt to the ongoing turnaround at AOL (AOL).

Mary Barra -- GM

The company's incoming chief executive officer, who was selected to succeed Dan Akerson in December, takes over GM (GM) at a time when the company is enjoying a light debt load and an acclaimed new lineup. Yet Barra will be under a microscope -- unfairly so -- because she carries the title of the only woman to ever lead a major automaker. GM also needs to develop a stronger sales strategy for its European operations, and Barra will need to focus on coming contract negotiations with United Auto Workers in 2015.

Jamie Dimon -- JPMorgan

In May, the CEO and chair of JPMorgan (JPM) was reelected to both posts by two-thirds of its shareholders. But that was before the nation's biggest bank forked over $13 billion to end civil investigations into its sale of mortgage-backed securities and prior to its payment of a reported $2 billion to resolve charges connected to the Bernie Madoff Ponzi scheme. The monster settlements -- and the liability they suggest -- don't reflect well on Dimon, but it would be foolish to count him out. These are one-off payments, and JPMorgan's banking, loan-making, and trading still make tons of money.

Brian McAndrews -- Pandora

Call it the Pandora (P) pickle: how can the Internet radio service rein in its royalties -- the fees that ate up half of its $427 million in profits in fiscal year 2013 -- without losing users? As of September, that problem is McAndrews's to solve. Past attempts haven't worked. Its strategy in February to restrict listeners to 40 hours of free listening per month was quickly aborted when user hours dropped. And its decision to buy a South Dakota radio station to access lower "station manager" fees and its backing of a now-defunct bill in Congress that would have reduced its rate were opposed by the music industry, which claims that Pandora doesn't pay artists enough in the first place.

Whoever takes over at Microsoft

The considerable time Microsoft (MSFT) is taking to choose its next leader reflects the challenges he or she will face. Simply put, the new CEO must find a way to make up for the decade or so the Redmond, Wash.-based company lost to Google and Apple. A few areas of focus? Smartphones, tablets, web search technology, cloud computing, wearable technology, and online advertising. Editor's note: A previous version of this slide incorrectly stated that Microsoft was based in Redwood, Calif. The company is based in Redmond, Wash.

CEOs who will be on the hotseat in 2014