With the surge in mergers and acquisitions, it's hard not to make money. Yet in the investment-banking world, investors expect near perfection. So while Jefferies Group (NYSE:JEF) has posted strong results this year, it's still not enough to get investors excited.

Yesterday, the company announced its second-quarter results. Revenue spiked 42.2% to $465.5 million, and net income rose 49% to $67.8 million, or $0.45 per share.

The key driver was Jefferies' investment-banking machine. The division's revenues surged 81% to a record $223.1 million as the company continued to benefit from the growth in energy and tech deals. The weakness continued in asset management, with revenue falling about 40% to $13.3 million.

To keep revving the growth, Jefferies realizes it needs to get aggressive with hiring and acquisitions. So it bought two companies over the past couple of months. First, there was a deal in late May for LongAcre Partners, which focuses on European media and Internet deals and last year provided advisory services on $6 billion in transactions. The amount of the deal was not disclosed.

Then there was the acquisition of Putnam Lovell in late June, for an undisclosed amount. The firm focuses on transactions in the financial-services sector and has advised on deals such as State Street's (NYSE:STT) acquisition of Currenex. Terms of this deal have also not been disclosed.

Now there is even chatter that Jefferies itself may be buyout bait. The firm does have an attractive platform that caters to the needs of middle-market clients -- and that's not easy to develop.

Just last week, Lazard (NYSE:LAZ) agreed to buy Goldsmith Agio Helms & Lynner, which is a middle-market advisory shop. Might other big players, such as Goldman Sachs (NYSE:GS), Lehman (NYSE:LEH), and Morgan Stanley (NYSE:MS), do similar deals?

It seems reasonable. But for Foolish investors, it's still a good idea to avoid buyout speculation.

As for Jefferies, I'm still cautious. While I think the growth will continue, the stock price may remain lackluster as investors remain quite demanding. It's probably better to wait some time before the acquisitions, new hires, and the overseas expansion start hitting critical mass.

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Fool contributor Tom Taulli, author of The Complete M&A Handbook, does not own shares mentioned in this article. He is currently ranked 3,203 out of more than 60,000 participants in Motley Fool CAPS. The Fool has a disclosure policy.