Five years ago Lehman Brothers (LEH) was trying to shake the image of being mainly a bond house and acquired asset manager Neuberger Berman for $2.6 billion. The deal was a great idea, not only because it increased Lehman's equity exposure and was a very stable, predictable business, but also because NB is truly one of the best asset managers around.

Given Lehman's recent troubles, the company is considering a sale of the unit and some are speculating that selling the entire division could fetch as much as $8 billion. Tripling their money would clearly be a coup, but in reality Lehman should hold onto NB if at all possible. The acquisition was a brilliant move and the current state of the investment banking world makes it clear that having a Neuberger Berman is a solid foundation in an otherwise shaky world for pure investment banks.

Now more than ever, diversification is going to be crucial for the industry, but being forced to sell NB would be a step in the exact opposite direction.

Full Disclosure: No position in Lehman at the time of writing. Peridot was invested in Neuberger Berman when Lehman announced the acquisition in 2003.