NEW YORK (CNNMoney.com) -- Forget about any economic weakness - real or perceived. When companies want to do a merger, acquisition or stock offering, they're still looking to Goldman Sachs for investment advice.

That continued sentiment helped the nation's third-largest brokerage post much better-than-expected third quarter earnings Tuesday - an accomplishment that lifted Goldman Sachs (up $4.90 to $155.90, Charts) shares more than 3 percent in NYSE trading.

The company posted third quarter earnings of $3.26 a share, up a penny from last year, and significantly higher than analysts expectations of $2.97 a share, according to earnings tracker Thomson First Call.

Goldman's earnings, which kicked off earnings season for the major brokerage firms, were strong in the face of some serious economic and market challenges.

Analysts in recent weeks slashed earnings estimates for the company - along with competitors Lehman Brothers (Charts), Bear Stearns (Charts) and Morgan Stanley (Charts), which will all issue quarterly reports within the next two weeks - citing concerns that weakness in the markets and expectations for a slowdown in the economy could curb companies' enthusiasm to complete equity offerings and reduce M&A activity.

But Goldman Sachs financial chief David Viniar said during the company's third quarter earnings call with analysts that its backlog of investment deals remain unchanged from the end of the second quarter.

"There's still a lot of corporate activity and a lot of dialogue with corporations," Viniar said. "That's reflective in the backlog."

Viniar added that if the market remains skittish and interest rates rise considerably, that could impact interest among the financial sponsors that provide backing for deals going forward.

"Financing is key to the great growth we've seen," he said, adding that a bad economic environment would undoubtedly put in a crimp in M&A deals and equity offerings.

While Viniar said there continues to be uncertainty in the near term, in the medium and long-term, he remained optimistic about the company's prospects and competitive position.

That's good news for Wall Street, which had become increasingly concerned about the outlook for the big brokerages. Someanalysts wondered if the traditional summer doldrums would lead to a prolonged downturn in earnings for the banks after an unusually strong period of equity underwriting and growth in the capital markets.

CreditSights analyst David Hendler said he anticipated some deceleration from the previous quarter. But given Goldman Sachs' diverse business lines, the company was able to continue to show merger activity growth even in a tough environment.

He added that the company will likely continue to do well even if the economic environment turns sour.

"It's a franchise strength for them," he said. "And if the economy does slow, there may be some desire (among corporations) to do more M&A to reposition for growth."

And that would serve to benefit Goldman Sachs.

Still analysts worried that Goldman and its peers would succumb to weakness in their trading businesses. To that end, Goldman did show some declines in its trading and principal investments unit.

That business saw revenue fall to $4.72 billion, a 7 percent drop from last year and 32 percent lower than its unusually strong second-quarter results. Its flagship fixed income, currency and commodities (FICC) trading division posted revenue of $2.74 billion - up 4 percent from third-quarter results in 2005, but down 36 percent from last quarter.

And investment banking, which was the wild card given reports of a slowdown in M&A activity and equity offerings in the third quarter, posted a solid year-over-year jump in revenue, although there was a 16 percent decline from the second quarter.

Analysts called the report a mixed bag, but were impressed by Goldman's resilience in a tough third quarter environment.

"Pessimists can point to the slowing of principal and client-related trading, while optimists can cite the continued strength in investment banking activity," said David Easthope, analyst at independent research and consulting firm Celent LLC. "Despite the slower and hotter summer months, it seems like the Goldman bankers have not been sitting on a beach."

Now all eyes are turned to Lehman Brothers and Bear Stearns, which are scheduled to report their third quarter earnings over the next two days. Morgan Stanley is slated to report its earnings on Sept. 20.

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