A group led by financial services firm Guggenheim Partners, which bought Lisle, Illinois-based ETF issuer Claymore last year, has reached a deal to acquire Security Benefit Corp., the parent company of ETF Manager Rydex SGI.The group led by Guggenheim will make an investment of approximately $400 million for a controlling interest in Security Benefit. According [...] Related Stories: ETF M&A Heating Up: Guggenheim To Buy Claymore Christian Magoon On The Claymore-Guggenheim Merger and The Future Of The ETF Industry Claymore Files For Another China ETF