Stifel is now negotiating key aspects with Barclays, although a deal is not certain and Barclays could go back to other bidders that have made offers, the people said this week.
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A deal for the business—the former brokerage arm of Lehman Brothers—could come as early as next week, the people said.
The price being discussed could not be learned.
The sources requested anonymity because the matter is not public, and a spokeswoman for Stifel and a spokesman for Barclays declined to comment.
Barclays has been reaching out to potential acquirers for the business for several weeks because it views it as non-core, sources told Reuters.
Stifel Chairman and Chief Executive Ron Kruszewski has acquired several, mostly troubled retail brokerage and investment banking firms since 2005. The once low-key St. Louis firm that specialized in municipal bonds is now a national presence serving individual investors and middle-market companies.
Kruszewski, a firemans son who became CEO in 1997, has paid relatively low prices for the acquisitions, but often provides generous pay packages to retain employees of the firms.
A deal between Stifel and Barclays would come on the heels of Stifel's agreement in February to buy Alabama-based Sterne Agee for about $150 million.
Sterne Agee has about 730 brokers, who together with those now working at Barclays Wealth Americas, would bring the Stifel brokerage force to more than 3,000.