The fast-paced success of the roaring 1980s seems have returned for investment banks, and top-tier players aren't the only ones benefiting.

Look at mid-tier firm Jefferies (NYSE:JEF). In the first quarter, the company posted net income of $58.4 million, or $0.82 per share. This was up from $36.7 million, or $0.56 per share, in the year-ago period. Revenues surged 52% year over year, to $524 million.

Given Jefferies' strong performance over the past few years, Wall Street analysts had high expectations for this earnings release. Nonetheless, the company still beat analysts' consensus estimates of $0.64 per share. Jefferies also said it would split its stock 2-for-1 and boost its dividend from $0.075 to $0.125 per share -- its fifth dividend increase in three years.

The robust investment-banking climate certainly helped Jefferies' results. M&A, private equity, venture capital, and trading have been growing at a nice clip. There are also signs that the IPO market is perking up.

Yet Jefferies is also benefiting from some shrewd moves undertaken during the subdued investment climate of 2001-2003. The company bulked up its technology advisory services by purchasing Broadview International LLC, and followed up with the 2002 buyout of Quarterdeck Investment Partners, a middle-market investment bank specializing in defense and aerospace. Jefferies bought these companies when the investment-banking sector was in terrible shape; the relatively low purchase prices made these deals ultimately accretive.

Recently, Jefferies purchased Randall & Dewey, a leading M&A advisor to the global oil and gas industries. With oil prices high, Jefferies should benefit from the consolidation of the industry. The sector is awash in plenty of cash to enable buyouts, so it seems likely that the bigger players will start buying smaller ones -- and those smaller players will likely need representation. Plentiful IPO activity in the energy sector could help Jefferies, too.

In other words, the company has a fairly diversified investment-banking platform that's particularly focused on the midlevel market, where the big banks are less likely to compete. Jefferies continues to innovate, as well; it recently partnered with MassMutual to market services to middle-market companies. (MassMutual invested $175 million in the deal.)

To further expand its capital base, Jefferies sold $500 million in senior debentures in January, giving the company the liquidity to pursue long-term opportunities. In the meantime, it seems the capital markets will remain strong -- and so should all of Jefferies' business segments.

Fool contributor Tom Taulli does not own shares mentioned in this article.