Former Treasury Secretary Robert Rubin has resigned as a senior counselor and a director of Citigroup, according to The Wall Street Journal. Rubin has been under pressure to take responsibility for the company's turmoil after the financial giant lost $20 billion last year and received a government bailout over $45 billion. Rubin, for his part, benefited from $115 million in compensation since 1999, aside from stock options. Citi's stock has tumbled 90% since the end of 2006. Rubin is expected to turn his focus to non-profit work.