Piper Jaffray Cos. has again expanded its investment banking business with the purchase of Houston-based Simmons & Co. International, an independent investment bank specializing in the energy industry. Minneapolis-based Piper Jaffray said it will pay about $139 million ($91 million cash and $48 million in restricted stock) for Simmons & Co. Simmons & Co. generated $96 million in revenue in the 12 months that ended June 30, including $65 million from advisory services. Founded in 1974, the firm...