On Wall Street, when one bird flees, a flock sometimes follows.

This week, Jefferies' ( JEF) recruiting efforts prompted an exodus of some of Bank of America's ( BAC) derivative masterminds. The firm scooped up, in total, eight former and current Bank of America employees.

The first migration was Vlad Portnoy, a Bank of America quantitative strategist. Portnoy will run the quantitative strategies group at Jefferies. Structured products, whose complexity often requires a doctorate to comprehend, are especially attractive to hedge fund managers. As equity trading continues to mature, investment banks must develop increasingly sophisticated ideas for their clients, to keep from losing them.

Some of Portnoy's allies followed his move, with six other Bank of America financial engineers and technologists joining Jefferies' quantitative strategies group, including Valeri Smelyansky, Branko Stojkovic and Victor Miller.

Thursday, Jefferies announced another hire: equity products specialist Jason Griffith. Griffith will begin as co-head in the equity products group with former colleague Ross Stevens and will work to expand the firm's equity derivatives products. Before joining Jefferies, Griffith was a founding member of Banc of America's equity derivatives platform. Most recently, he ran Societe Generale's structured product sales practice, after the firm acquired the U.S. structured investments division at Bank of America.

"Having focused over the past few years on driving the growth of investment banking and asset management, we are now devoting greater attention to expanding Jefferies' sales and trading effort, as demonstrated by a series of strategic hires in recent months," commented Richard B. Handler, chairman and chief executive officer of Jefferies.

Over the past two years, Jefferies has built its investment-banking and asset-management businesses. The firm, which at one time was primarily made up of trading business, has made a mark in middle-market underwriting.