“If you buy a railroad, you can’t move it to China or to India or anyplace else. You are betting on the United States. I can’t think of a surer bet.”

- Warren Buffett, explaining Berkshire Hathaway’s (BRKB) $44 billion buyout of Burlington Northern Santa Fe (BNI).

Click here to see Buffett talking about his biggest deal ever with CNNMoney anchor Poppy Harlow.

While the size was a surprise, the bet on America was not. In September, at the Fortune Most Powerful Women Summit, Buffett said he was busy buying stocks and had lots of faith in the U.S. “Our genius in the U.S. is not avoiding problems. It’s overcoming problems,” he told my colleague Carol Loomis.

Their on-stage conversation–recalling the collapse of Lehman (BCS) and its awful aftermath, and also looking ahead–was terrific. We ran snippets earlier on Postcards. But since Buffett is back in the news, we’ll share all 22 minutes:

And if you’re curious to know what it’s like to work for Buffett, read “How Warren Buffett manages his managers.”

by Jessica Shambora

Yesterday we told you that Google (GOOG) tops the list of heavyweight stocks in terms of “market capitalization per employee.” There’s $8.6 million in stock-market value riding on every Googler who works for the company.

It’s an odd metric, yes. The post generated some amusing comments. David Emery in Reston, Virginia wrote, “This seems to be a good justification for Google’s well-known investment in/pampering of their employees. Happy employees generate value-per-employee, I suspect.”

Another reader noted that Gilead (GILD) beats Google on this particular metric. The biotech company, with $40 billion stock-market value and 3,400 employees, boasts an impressive market cap/employee of $11.7 million. The power of pharmaceuticals.

So, what are the biggest U.S. companies by market capitalization?

It’s fascinating to see that Apple (AAPL) — which, due to strong earnings and new-product excitement this week, rose to the top five — stands a chance to eclipse Wal-Mart (WMT) in stock-market heft. Apple, though, is still a long way from touching mighty Exxon Mobil (XOM).

The 10 largest U.S. companies by stock-market capitalization are:

1. Exxon Mobil: $353.23 billion

2. Microsoft: $249.9 billion (MSFT)

3. Wal-Mart: $194.3 billion

4. Apple: $183.88 billion

5. JP Morgan Chase (JPM): $179.84 billion

6. Google: $175.93 billion

7. Procter & Gamble (PG): $167.3 billion

8. Johnson & Johnson (JNJ): $166.2 billion

9. General Electric (GE): $161.42 billion

10. IBM (IBM): $159.08 billion

P.S. Besides Gilead, do you know any companies that beat Google’s stock-market value per employee: $8.6 million?

By Jessica Shambora

When Apple (AAPL) passed the giants–General Electric (GE), Johnson & Johnson (GE), Procter & Gamble (PG), and even Google (GOOG)–in terms of stock-market value this week, we started wondering: What company in the universe has the highest stock-market capitalization per employee?

We ran the number and it turns out to be…Google!

Even as Apple has surged on the heels of Monday’s blowout quarterly earnings report–and news of upcoming products like its Tablet computer/e-reader–Apple’s $187.7 billion stock-market value translates to $5.8 million per employee.

That’s certainly impressive. It surpasses the market cap/employee of Exxon Mobil (XOM), Microsoft (MSFT) and Wal-Mart (WMT), which happen to be the only three U.S. companies whose total stock-market capitalization is higher than Apple’s today.

But Google is the champ in terms of human capital: Its current $175.5 billion market value translates to $8.6 million per employee.

How thrilling–or maybe frightening–to know that this level of investor confidence is riding on Googlers worldwide.

All eyes are on Goldman Sachs (GS), which announces earnings tomorrow. What goosed the stock…and then the banking sector and then the entire market today? Meredith Whitney’s upgrade.

It mattered–and helped send Goldman up nearly 5% to $149–because the famously bearish financial-services analyst, who helped bring down Citigroup and the banking sector two years ago, has been negative ever since. She announced her upgrade of Goldman at 2:24 a.m. At least that’s when the email from her company, Meredith Whitney Advisory Group, popped into my inbox this morning. This is Whitney’s first upgrade since she broke away from Oppenheimer in February to go on her own. It’s also her only “Buy” rating among eight stocks she follows.

So yes, Meredith Whitney finally turned…on one stock only. Don’t dare call her a bull on the market. She says in today’s Goldman report that her positive outlook “is deeply rooted in our sustained bearish stance on the U.S. economy and state of U.S. financials at large.”

She likes Goldman because she’s predicting “a tsunami of debt issuance” from federal, state, and local governments to shore woefully underfunded budgets. That, plus a surge in corporate debt issuance (to at least 60% of peak cycle levels, she says) will benefit Goldman, which along with Morgan Stanley (MS) is the last Wall Street giant standing. Survival of the fittest, precisely. The weak fall and the strong get stronger.

As for Whitney, she’s showing her muscle. Last week here at Fortune, we were talking about her as we began to assess the crop of candidates for this year’s Fortune Most Powerful Women in Business list, due out in mid-September. Last year Whitney ranked No. 35 on the list. We were wondering if she’s still got her mojo. Guess she does.

P.S. Whitney has sells on three stocks: Wells Fargo (WFC), Capital One (COF), and Citigroup (C).

Lots of people are now seeing light at the end of the global recession, but it pays to keep the dark clouds in sight. My Fortune colleague Shawn Tully does that in his just-published story about Ireland. As he notes, Ireland’s economy is suffering the deepest plunge of virtually any country outside of Iceland. And it’s not over yet.

To get a broader view of global risk, I called Ian Bremmer, the president of the Eurasia Group. Bremmer is an expert on geopolitical risk around the world, and his firm advises lots of well-known companies including Citigroup (C), NYSE Euronext (NYX), and PricewaterhouseCoopers. I don’t know Bremmer well, but when I saw him speak at a launch party for his new book, The Fat Tail, I was impressed with his finesse at describing a world at greater risk than ever in our lifetimes. Sallie Krawcheck, the former Citi exec who hosted the party for Bremmer and co-author Preston Keat, connected us. And we talked about danger and opportunity around the world. Here are excerpts from my chat with Bremmer:

What are fat tails?
Fat tails are one-in-100-year storms that increasingly happen every 15 minutes. They are extreme outcomes that normally you wouldn’t have to worry about.

Do thin tails become fat tails?
Yes. You had all these risks – thin tails – before the financial crisis hit. Now they’re fat tails.

Like what?
If you‘re an investor in Russia, six months ago you didn’t have to worry too much about that country going hard-authoritarian. That’s something that you now have to worry about.

What should investors in Russia watch for?
Public disagreements between liberals and hard-liners on policy. Social discontent in the rural regions.

You list 10 fat tails. How likely are they to happen?
These are not all things that we think are going to happen. But I would bet that a couple of them will happen.

Which ones are highest on your “likely” list?
Pakistan. I don’t think we’re close to having a failed state, as [Richard] Holbrooke recently said. The Taliban aren’t going to take over. Nukes aren’t going to end up in the hands of terrorists. But radicals taking over the tribal regions, combined with the economic crisis, could lead to enough social discontent that the military takes over.

Chances of that?
I’d say 30%.

What would that mean for global investors?
Investors might like it, short-term. It would lead to temporary stability. But this would not be a happy situation for the long-term stability of the region. It would mean more fractious relations with India and a constraint on Pakistan’s economic reform long-term. Military takeovers tend to be buffers against the worst scenarios, but also against the best scenarios.

Can fat tails be positive in the long term?
Yes. Political risk is not necessarily about things that can blow you up. Take Argentina. The fat tail there is actually an opportunity. The global recession is undermining the economy, and the government can’t handle the fallout well. As poll numbers continue to fall, you could see the President [Christina Fernandez de Kirchner] lose the election in June, and the Kirchners could be out. If the current Vice President [Julio Cobos] comes in as President, there will be much less state intervention in the markets, more openness in agriculture, and an improvement in market sentiment.

Resilience is more critical than ever—for people and countries. What countries look most resilient?
The U.S. is not going to lead the world out of the crisis. China will. It’s important to recognize that China didn’t have a banking crisis. There was a financial crisis in less than half the world, and there is a global recession. China has had an economic downturn. But China has put a massive stimulus in place. And they’ll come out of this fast.

Who else is resilient?
The Persian Gulf countries. They’re helped by small populations, cheap access to natural resources, and cohesive governments that can deal with a downturn. Brazil and Indonesia also have cohesive governments, which helps.

What about India?
Interestingly, India benefits from its decentralized government. The government is not being blamed for India’s economic problems—and that’s an advantage.

My Fortune colleague Shawn Tully just wrote a story about Ireland on the edge. How scary it is to see developed countries at risk of default this year. How do you see risk in Europe right now?
We’ll see very anemic growth there for a long time. I’m not an expert on default risk. But I will say, there’s increasingly more stability in the system. We’re no longer at risk of broad contagion.

In Friday’s Wall Street Journal, you wrote an op-ed that said Gordon Brown might not survive as Britain’s prime minister. What are the chances that he’ll be out this year?
I think it’s 50-50, honestly. There’s a real possibility. He’s not going to go easily. The underlying situation has gotten so bad that a strong conservative leadership – or any strong leadership – would be better than they have now. Britain should be one of the strongest supporters of the U.S. on collective security and climate change. But right now, Britain is in absolute nowhere-land.

Any more power shifts you care to talk about?
Everyone talks about Wall Street vs. Main Street. K Street has taken over both. New York used to be the financial capital. Now Washington is. Washington will determine who’s a winner and who’s a loser. Power has shifted from Dubai, the financial capital of the UAE, to Abu Dhabi. From Shanghai to Beijing. Mumbai to Delhi. The state is the principle economic actor. It’s a repudiation of the free-market system around the world.

Sounds like the end of capitalism.
It’s a problem for investors and for the robustness of economic growth. This system isn’t as efficient as the free market is.

“If you are in the investment business and you have a high IQ, sell 30 points to the next person. You do not have to be a genius at all. But you do have to have emotional stability, and you have to have some peace about your decisions. I don’t know how much is innate and how much can be taught. If you have that quality you will do very well. As I have said many times, it is simple, but not easy.”

–Warren Buffett at Berkshire Hathaway’s (BRKB) annual shareholder meeting in Omaha last weekend. Buffett’s theory that you don’t have to be a genius to make money investing is well known, but it bears repeating in these uncertain times where “emotional stability” and “peace” seem in short supply. After Friday’s closing bell, Berkshire reported a quarterly loss of $1.4 billion vs. a $1 billion profit in the same quarter a year ago. Among the culprits: write-downs in derivatives, falling oil prices, and the retail crunch. Strong profits in insurance underwriting shored Berkshire. Shares were up slightly in after-hours trading.  –Jessica Shambora

“Our stock price is not an indication of our financial strength.”

– Citigroup (C) CEO Vikram Pandit in a memo to employees sent Monday night. How ironic that Citigroup shares jumped 38% on Tuesday. Citi’s stock is so low that it took a gain of just 40 cents to rise so much, percentage-wise, and close at $1.45.  Citi’s pop was part of a overall surge in the market that had the Dow up 379.44, or 5.8%, today. –Jessica Shambora

Bank-industry analyst Meredith Whitney, one of FORTUNE’s Most Powerful Women and the subject of our cover story last summer, is all over the place this week. An op-ed, “Credit Cards are the Next Credit Crunch,” in today’s Wall Street Journal presents a dreadful outlook for consumer spending. She says that she’s upped her estimate for how much banks will yank credit lines to consumers–by $2 trillion this year and a total of $2.7 trillion by the end of 2010.

Lenders have to retrench, having extended credit way too freely for the past 15 years. But what’s really scary about such a dramatic pullback, Whitney says, is that lenders will be taking credit away from people who are able to pay their bills. And given that two-thirds of the U.S. economy depends on consumer spending, this will seriously retard any recovery.

Whitney doesn’t name lenders in her WSJ piece, but in a report that she sent to clients today, she lists the five companies that control two-thirds of the market: J.P. Morgan Chase (JPM), Bank of America (BAC), Citigroup (C), Capital One (COF) and American Express (AXP). While customers have a mortgage loan from just one company–a “monogamous relationship,” she notes–the typical credit-card customer borrows from more than one of these lenders. So, she suggests: “These lenders need to work together…by setting consortium guidelines on credit. We, as Americans, are all in the same soup here, and desperate times are requiring of radical and cooperative measures.”

Meanwhile, there’s a very good Q&A, titled “The Straight Shooter,” with Whitney in a magazine called Power, just out. In the interview, she talks about chatting up Warren Buffett (BRKB) at Fortune’s Most Powerful Women Summit last October. The topic: paper routes. Here’s an excerpt:

“When I was about eight or nine, I told my mother that I had to have my own money. And that led to the newspaper route. It was just run-around money. In fact, the first real thing I bought was a watch for my mom, which she still has. I was very good at delivering papers and was able to buy up other paper routes. At the FORTUNE women’s summit in October, I didn’t want to bug Warren Buffett, who was there. But I needed to talk to Carol Loomis [FORTUNE senior editor-at-large], who was with him. I couldn’t help myself and said to him, “Thank you for providing such comfort at a time when most Americans are scared to death.” And he said, “Tell me about your paper route.”

If you had a real paper route, not just a casual hobby, you will talk about it all day long. And I said, “Well, I’ll tell you about my paper route, but I need to know a few things. Was yours a bike route or on foot?” And he said, “Bike.” And I said, “That is such a different experience because my paper route was on foot, so I don’t know if we can compare ourselves.” I would go up to the front door, put the paper behind the screen door and get better tips. And so I asked Warren Buffett, “What was your best tip?’ And he said, “$1.” I asked him what that would be adjusted for inflation. And he said, “$10.” I got $20.”

As you may know, Whitney last month quit Oppenheimer & Co. to set up her own shop, Meredith Whitney Advisory Group. If she carries her paper-route business sense into adulthood, I think she’ll make a go of the new venture.

Barack Obama’s hair is turning gray. The New York Times reported the other day that a President typically ages two years for every year in the job. Thank goodness our new President is only 47 years old. The way things are going right now, I suspect he’ll age twice as fast as other Presidents.

We learned this week that things are worse than we thought. General Electric (GE) CEO Jeff Immelt, who used to be one of the world’s most admired bosses, saw his stock dip below $6 on Wednesday, down from $30 a year ago. (It’s now nosing toward $7.) Citigroup (C) CEO Vikram Pandit watched his shares drop below $1–a dollar! The stock-market capitalization of Citi, with shares now trading at $1.02, has sunk to $5.6 billion. Meanwhile General Motors’ (GM) market cap is below $1 billion. GM’s auditor, Deloitte & Touche, said yesterday that the automakers’ survival is in “substantial doubt.”

And today we learned that America’s unemployment rate has reached a 25-year high. Job losses in the past six months topped 3.3 million. “These days, people have either two jobs or no job,” Andy Serwer, my boss here at Fortune,  likes to say. I feel it. Between writing for the magazine, blogging, and chairing Fortune’s Most Powerful Women Summit, I’m pushing myself like never before. I was in my office until 2:45 a.m. Thursday morning. I hadn’t stayed that late since the ’90s. Made me feel young, actually.

I’m lucky. I have a job. And one that I love. I look around my office today and I see the smartest, hardest-working people I’ve ever been around. (And I’ve been here at Fortune for 25 years.) Today, slackers simply do not survive. Don’t you wonder if these twentysomethings–the enterprising and lucky ones who have jobs today–will emerge as a new Greatest Generation of workers? They might turn out to be better than we are.

“You have to say that we will be in this for a long time and we will turn this into a defining event, a big catalyst to make ourselves a much stronger enterprise. Our characters are being forged in a burning, searing crucible.”

– Jim Collins, management guru and author of Built to Last and Good to Great, in a Q&A with Fortune’s Jennifer Reingold. The crucible Collins refers to got even hotter today as the Dow slumped to a six-year low, dropping 89 points, or 1.2%, and closing at the lowest point since Oct. 9, 2002.

But drawing on his work from the past several years studying how companies manage to navigate through turbulent times, Collins concludes that there is a silver lining: “One of the big lessons we’ve learned is that turbulence is your friend. If you were disciplined and prepared before the storm came, you should be thankful for those times.” –Jessica Shambora