Stifel Financial, the New York-listed brokerage and investment banking firm, has agreed to acquire financial services provider Stone & Youngberg for an undisclosed amount.

California-based Stone & Youngberg has a wealth management unit, adding around four offices staffed by 30 financial advisors to Stifel’s private client group. Stifel, which is based in St Louis, Missouri, is also expanding its public finance, institutional sales, and trading and bond underwriting offerings with the acquisition.

Stone & Youngberg’s private clients will have access to greater sales distribution due to the size and strength of the Stifel private client group, said Stone & Youngberg president and chief executive Kenneth Williams.

The transaction is expected to close on 1 October 2011, subject to customary regulatory approvals.

For the first quarter of this year, Stifel Financial reported net revenues from its Global Wealth Management business of $238.4 million, an increase of 19.6 per cent year-over-year, and broadly flat on a consecutive basis. Pre-tax operating income at the GWM unit was $61.5 million for the quarter, up from $39.2 million in the first quarter of 2010.

Net revenues at Stifel’s private client group, the major part of the global wealth management business, were $229.5 million.