 Shares of Medallion Financial Corp. MFIN, -0.71 plummeted 56.5 toward a 13-month low in premarket trading Wednesday, to pace all premarket decliners, after the Securities and Exchange Commission charged the New York-based bank holding company and its Chief Operating Officer Andrew Murstein for engaging in fraudulent schemes to boost its stock price. The SECs complaint alleges that Medallion and Murstein engaged in illegal touting of its stock by paying media strategy company Ichabods Cranium Inc. to place positive stories about the company on various websites, including Huffington Post, Seeking Alpha and TheStreet.com. 