Morgan Stanley (NYSE:MS) rounded out earnings announcements for investment banks on Tuesday, and "best third quarter ever, third best quarter ever" seems to be the phrase of the moment. The investment bank's strong results confirm the trend established by three of its peers last week -- Goldman Sachs (NYSE:GS), Bear Stearns (NYSE:BSC), and Lehman Brothers (NYSE:LEH). Broker-dealers have emerged from the third quarter without any war wounds, despite a difficult environment at the start of the period. (In the following discussion, all comparisons refer to the prior-year quarter, unless stated.)

Net income from continuing operations was $1.8 billion on net revenues of $8 billion, advancing 59% and 15% respectively. Earnings from continuing operations were $1.75 per diluted share, a 61% increase and well ahead of the consensus estimate of $1.37 per share.

Morgan Stanley's stalwart Institutional Securities segment (63% of net revenues for the nine months to Aug. 31) put in a terrific performance, with a 55% increase in net revenues to $5 billion, driven by growth across all activities (including equity and fixed income trading, underwriting, and M&A). Call it nitpicking, but I was surprised to hear CFO David Sidwell say that the equity underwriting pipeline is "down significantly." His assurances that this isn't tied to any loss in market share appear inconsistent with his competitors' reports that their pipelines remain very healthy.

Along with Merrill Lynch and longtime rival Goldman Sachs, Morgan Stanley is one of the "best in class" global investment banks, so it comes as no surprise that its core Institutional Securities segment performed well. Current (or potential) Morgan Stanley shareholders should be more concerned with the state of the laggard Wealth Management and Discover units. On both fronts, the quarter's results appear to confirm that management's turnaround plans are paying off. Net revenues for Wealth Management and Discover increased 9% and 15% respectively, and gains in pre-tax income were even more significant. Furthermore, the progress for the quarter is in line with trends for the first nine months of this fiscal year.

These improvements won't help to revive discussions regarding a possible spin-off of the Discover credit card unit. That's a shame, because I'm not convinced this is a business the firm should be involved in. While supporters of the 1997 merger between Morgan Stanley and Dean Witter might argue that the activity adds stability to earnings, I don't see much merit to that. Some earnings volatility is a natural consequence of an investment bank's operating model, which turns on the ability to bear and manage a wide variety of market-related risks. For investors who aren't comfortable with this model, "universal banks" such as Citigroup (NYSE:C) and Income Investor picks JPMorgan Chase (NYSE:JPM) and Bank of America (NYSE:BAC) are better alternatives.

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Fool contributor Alex Dumortier has no beneficial interest in any of the companies mentioned in this article. He welcomes your (constructive) feedback. The Motley Fool has a strict disclosure policy.