Since the credit crisis began, Goldman Sachs has been one of the safest bets in the financial sector.

But it bears reminding that even the most secure building in a war-torn city is vulnerable to getting hit. And Goldman investors are now hearing that reminder loud and clear.

In the past week, one Wall Street analyst after another has downgraded Goldman's outlook for the quarter and the year. Its shares are down 10 percent just in the past week.

Today's 2 percent fall comes after the analyst who covers Goldman for Fox-Pitt cut his third-quarter estimate to $1.95 from $3.26. This follows downgrades last week by analysts at UBS, Oppenheimer, Deutsche Bank, and others.

Nothing happened to spur the downgrades except that all of the Wall Street analysts seem to have concluded simultaneously that the weakness in global indexes is likely to impact Goldman more than anyone previously thought.

While Goldman escaped much of the turmoil following the collapse of the mortgage market, it is more vulnerable than its peers to a collapse in global equities. Many major indexes around the world are down more than 20 percent.

But the shine hasn't completely tarnished from Goldman's golden image. The firm is raking in fees from some of the biggest mergers so far this year, Dealbook notes. It's set to take in $40 million for advising Anheuser-Busch on its sale to InBev. It already received $46 million for advising Wrigley on its sale to Mars.

And, despite the recent analyst downgrades and its slumping share price, Goldman has still managed to outperform its peers. In the past three months, Goldman's shares have fallen less than those of Merrill Lynch, Citigroup, J.P. Morgan, and Lehman. Its share decline matches Morgan Stanley's for the period.

Goldman's quarter ends this month, and it will report earnings in mid-September. Wall Street analysts were wise to readjust their expectations for the bank, but it's not time to rip the yellow jersey off Goldman just yet.