Investing icon Warren Buffett took his own advice Tuesday – getting “greedy when others are fearful” – when he ignored the banking-sector bonfire and slapped down a cool $5 billion for a stake in Goldman Sachs Group Inc. (GS). By literally putting his money where his mouth is, Buffett’s actions – and reputation as a shrewd bargain hunter – restored some of Goldman’s luster and helped bolster investor confidence in the U.S. banking system.

As the ongoing effects of the capital markets credit crisis continues to be felt, US government financial leaders have urged Congress to make a speedy intervention, says Jennifer Yousfi in Morning Morning. Foreign banks capitalized on US distress by snapping up assets at bargain prices.

With the commercial-paper market evaporating – causing its ability to operate to do the same – Morgan Stanley escalated its frenetic search for a well-capitalized partner to help it restore investor confidence. Morgan Stanley shares have lost more than 40% in the past week, leaving Morgan Stanley Chief Executive John J. Mack seeking a tie-up with a commercial bank.

With the stock market in turmoil, it’s a good time to check in on what Warren Buffett is doing with his portfolio. Buffett’s Berkshire Hathaway Inc. (NYSE:BRK.A, BRK.B) has struggled in the first half of the year. Money Morning’s Jason Simpkins says $3.5 billion of Berkshire’s recent $4-billion shopping spree is still unaccounted for…

Since March, shares in Warren Buffett’s investment vehicle, Berkshire Hathaway (NYSE:BRK.A, BRK.B), have plunged 23%.

The Class A shares closed Friday at $116,650 each, down from their 52-week high of $151,650 (the Class B shares represent 1/30th of the Class A shares).

However, Money Morning’s Horacio Marquez says Berkshire’s share price is merely a reflection of the slowdown in the US economy. And with shares now at bargain prices, it’s a perfect opportunity to take a stake in one of the best investment portfolios on the planet…

There are scads of books on the market purporting to tell the story of investing guru Warren Buffett, says William Patalon III in Money Morning. But if you really want to learn about Buffett the man and Buffett the investor, there’s really only one biography worth reading…

Although consumers and businesses have gotten a bit of a reprieve at the gas pump as of late, says William Patalon in Money Morning, the escalation in oil prices we’ve seen over the past year has led to some major changes in overall consumer behavior. Many car-owners have dumped their gas-guzzling pickup trucks and SUVs at the nearest used-car lot and used the proceeds to buy some gas-sipping rides.

Valero Energy Corp. (NYSE: VLO), the largest independent refiner in the U.S. market, is a well-known and avidly traded name. Despite being a member of the super hot energy sector, Valero has seen its stock price collapse from its 52-week high of $75.75 to Friday’s close at $34.72 (a 54% decline).

US stock markets began to show signs of life on Friday. But many investors are still steering clear of stocks until a clear trend emerges.

One sector that’s taken a pummeling recently is insurers, says Ian Davis in The Growth Stock Wire. The Datastream Property and Casualty Insurance sector has lost 28 percent of its value since last summer.

This could lead to a great profit play when the time is right. Ian is an expert in finding stocks that are hated, cheap and in an uptrend. Right now, the insurance sector is certainly hated and cheap… the trick is finding the right moment to buy in. More from Ian…

The Dow Chemical Co. (DOW) yesterday (Thursday) announced its plans to buy rival Rohm and Haas Co. (ROH) in an $18.8 billion deal, $3 billion of which will come from Warren Buffett’s Berkshire Hathaway Inc. (BRK.A, BRK.B). News of the Dow buyout sent Rohm and Haas shares soaring over 60% by midday in New York.