Axios

Under Armour shares fell more than 28% on Tuesday, following a disappointing earnings announcement in which it dramatically dialed back expectations for revenue growth in 2017.

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Data: Money.net; Chart: Andrew Witherspoon / Axios

Why investors are grumpy: Under Armour is a quickly growing company, gunning for well-established brands like Nike. It's stock price relative to its actual earnings has been more than three times the average consumer goods firm, and that means that investors must see very large, continuous revenue gains to continue to hold the stock. Even though Under Armour projects 11% or 12% top-line growth this year, that was roughly half what analysts were expecting.

Sean Spicer held a tumultuous briefing this afternoon with the White House press corps, but hopefully this weekend will be a little more relaxed as he announced that President Trump will be in Mar-a-Lago (or "the Winter White House") for the weekend, departing on Friday.

1. "It's not a ban": @realDonaldTrump at 8:31 AM yesterday, "If the ban were announced with a one week notice, the 'bad' would rush into our country during that week. A lot of bad 'dudes' out there!"
2. On the battlefield: Spicer dodged the question when asked if Trump still believes in targeting the families of terrorists, but he did pledge that no American citizen would ever be targeted in a counterterrorism strike.
3. On the Yates firing: "This isn't about joining the government to execute your ideas or opinions ... If they don't like it, they shouldn't take the job. But it's the President's agenda that we're fulfilling here."
4. SCOTUS: "We've got an individual that I think is going to have widespread bipartisan support." Spicer deferred to Mitch McConnell when asked if Trump supports the Senate invoking the "nuclear option" for Supreme Court nominees.
5. At war with the media: Tensions ran high between Spicer and the press corps. When pressed on POTUS' tweet, Spicer said, "He's using the words that the media is using." He further told reporters, "You are part of the confusion." He also specifically cited the New York Times report on the executive order as "false reporting." Watch it below:

Warren Buffett told Charlie Rose on Friday that since the election day, his firm, Berkshire Hathaway, has bought $12 billion in stock.

This represents a shift of strategy for Buffett, who was a net seller of stocks in the first nine months of last year.

Why this matters: Even Buffett, who was a Hillary Clinton supporter, recognizes that the pre-election fear that a President Trump would destabilize the global economy was overblown. The 7% rise in the S&P 500 since election day has proven Buffett right, yesterday's declines notwithstanding.

Republican sources tell us that the Department of Homeland Security may issue "implementation guidance" that would allow for softening, and even policy changes, to President Trump's travel restrictions on migrants. The White House insists that any further guidance wouldn't constitute a walk-back.

But the internal conversation, led by Homeland Security Secretary John Kelly, reflects the widespread view among top Republicans that the current chaotic situation — beset with blame-casting, backstabbing and unintended consequences — is untenable.

Walmart takes on Amazon Prime: The retail giant, which last year acquired Amazon competitor Jet.com for $3 billion, is adding free two-day delivery for orders $35 and over and without membership fees (Amazon charges $99 a year).

Competing directly with Amazon is a big challenge. Walmart will now see if consumers prefer to trade membership fees (Walmart previously charged $49 per year) for a minimum order size. In any case, free two-day shipping has become "table stakes" in the online retail wars, said Jet.com co-founder Marc Lore.

Google employees rally for immigration: On Monday, more than 2,000 Alphabet employees gathered to march and rally at various company locations worldwide in protest of Trump's recent immigration executive order. Co-founder Sergei Brin and CEO Sundar Pichai gave speeches at the company's headquarters in Mountain View., Calif.

According to former YouTube executive Hunter Walk, Alphabet employees reached the $2 million mark in donations the morning after the company announced it would match donations to a legal defense fund.

The stock market as a whole is falling rapidly in the wake of Trump's immigrant ban, and the tech sector is following the same trendline.

Bloomberg's global technology tracker — which according to their reporters follows the world's most major tech companies — reveals that 90% of the 20 most influential tech stocks are plummeting as they try to deal with the fallout from Friday's executive order.

Why this matters: The tech industry is in freakout mode as it struggles with the threat of Trump limiting their outsourcing jobs or shutting down the H-1B visa program they use to recruit talent from overseas — and the market reflects that.

The Dow Jones fell around 200 points during trading on Monday morning, as the market reacted to President Trump's surprise executive order temporarily banning travel from several muslim-majority nations.

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Data: Money.net; Chart: Lazaro Gamio / Axios

As John Conlon, chief investment officer at People's United Wealth Management, tells CNBC:

"I think it also has to do with what the immigration policy represents [in terms of] the way the Trump administration is going to operate. The fact is that you've got a major policy that was implemented very quickly. That's causing uncertainty."

A new eMarketer study predicts programmatic display advertising will grow by more than 26% in 2017, even though most publishers admit they don't make that much money on it.

What is programmatic advertising? Have you ever been followed by an ad as you move from site to site that shows a pair of boots you almost bought on eBay? That's a programmatic ad. They are ads that can be targeted very specifically at scale, and are priced very low through an automatic bidding system.

Why is it growing? Major technology platforms, like Google and Facebook, have created an environment in which scale is a commodity. To keep up with those platforms, publishers have increased the amount of content they are creating, and they need an automated system to sell ads against all of that new inventory.

Why aren't they making much money? Profit margins can be low for this type of advertising because its extremely complicated to manage and takes a lot of infrastructure to monetize.

Why it matters: An increase in programmatic advertising suggests that scale will continue to dictate market needs in 2017. However, low profit margins, stemming from uncertainty in how to manage the platform, has led buyers to feel less confident in the platform. eMarketer predicts that when industry-wide quality and implementation standards are put in place, we can expect to see prices and revenues increase.

Democrat Ro Khanna, Silicon Valley's newest congressman, said that the government should be funding job-training programs to prepare people for the technical roles of the future.

When asked how efforts to train Americans for new roles could keep with the blistering pace of change, he said:

"So, the skills we need to teach are not 'you've got to learn Java programming or you've got to learn proficiency in Android technology.' The skill we have to give people is a technology proficiency — literacy that will allow them to continually adapt." — Rep. Ro Khanna, in an interview with Axios for C-Span's 'The Communicators' program

The rub: Tech companies often change the nature of work faster than the labor market can keep up. A prime example is Uber, which has created a new class of workers — ride-hail drivers — but is already beginning to test self-driving vehicles to replace drivers altogether.

Word on the street:. In a recent conversation with Axios about driverless trucks, new House Energy and Commerce Committee Chairman Greg Walden said that although automation is disruptive, "you're also not going to deny the innovation in technology either."

Khanna's workforce cred:

• He served as a Commerce Department Deputy Assistant Secretary under President Obama.
• He's taught economics at Stanford University and law at Santa Clara University Law School.
• He wrote a book: "Entrepreneurial Nation: Why Manufacturing is Still Key to America's Future"
• California Gov. Jerry Brown appointed him to the California Workforce Investment Board in 2012

Earnings season heats up this week, with more than 100 of America's biggest companies set to announce financial results. Here are the most important companies to watch

1. Aetna and Anthem: Two of the nation's largest health insurers release earnings Tuesday and Wednesday morning, respectively. Both companies have lost money due to participation in Obamacare exchanges, and both are attempting to consolidate with rivals as a result of the law. Look for clues as to how the industry will deal with antitrust oversight and Obamacare repeal.
2. Facebook: is being cautious projecting future growth of ad sales on its flagship product, but we'll begin to learn Wednesday evening how profitably it can leverage subsidiaries like Instagram, WhatsApp, and Oculus.
3. Amazon: the online retailer's "echo" products were the runaway hit of the holiday season. On Thursday, Amazon's reported revenues will tell us just how popular they were.
4. Drug companies: Several of the nation's largest drug makers will announce earnings this week, including Pfizer early Tuesday and Merck on Thursday. Look for indications on how the industry plans to combat efforts to force drug companies to negotiate prices with Medicare or other federal entities.

Snapchat, expected to file for its IPO late this week, "boldly compares itself with TV" in conversations with investors, per Mashable. One media executive who talks to the big platforms said: "Facebook, Amazon, even Apple are willing to write massive checks, tens of millions, hundreds of millions, to build specific content for that platform."

Why Snapchat plans more shows: "Few on the street recognized Peter Hamby, Snap's head of news and host of 'Good Luck America,' when he was a political reporter at CNN. Now, he's the 'Snapchat guy.' Exclusivity, Snapchat says, means quality."