Lehman Brothers (NYSE:LEH) broke the suspense today by finalizing a deal that's been splashing the newswires for nearly a month. The investment bank will officially acquire Neuberger Berman (NYSE:NEU), a premier asset management firm, for $41.48 per share in cash and stock, valuing the deal at over $2.6 billion.

This is a nice move for Lehman, as it provides diversification to the bank's revenue stream and gives it access to some high-growth, high-margin segments of the market. But today's action speaks to a larger trend of consolidation in the asset management arena that's been going on for some time now and shows no sign of letting up.

Despite the woes experienced by large investment banks, the small- and mid-tier asset managers have held up well. This is partly due to high net-worth clients seeking a more personal, customized relationship and capital preservation strategies in an ugly market.

Thus far, the majority of the acquisitions in this segment have taken place between these smaller firms, but the trend is now spreading to the larger investment banks and broker dealers.

Eaton Vance (NYSE:EV), itself a product of a 1979 merger, is one of the mid-tier players that's been on an acquiring spree for years now. It was arguably one of the first companies to make an aggressive foray into both institutional and individual asset management.

In 2001, Eaton acquired a 70% stake in Atlanta Capital Management for $70 million in cash and stock and an 80% interest in Fox Asset Management for $32 million and up to $30 million in future payments. Though small deals in comparison to today's announcement, they were definitely signs of things to come.

Fool writer and asset manager Zeke Ashton has spoken of Alliance Capital Management (NYSE:AC) in the past, and with good results. The firm became one of the largest asset managers with its 2000 purchase of Sanford C. Bernstein.

Neuberger, in addition to its 2002 acquisition of LibertyView Capital Management, has grown its assets by drawing money managers and their existing clients into its ranks. It now has over $56 billion in assets under management.

This trend isn't likely to stop with today's deal. Though these firms have been performing extremely well on their own, Eaton, Alliance, and any number of other mid-tier acquirers ultimately could themselves become acquisitions. Provided the price is right, these deals look awfully appealing to the ailing investment banks.