In 1999, affirming his career-long interest in markets, Rubin joined Citigroup as a board member and as a participant "in strategic managerial and operational matters of the Company, but [...] no line responsibilities". The "Wall Street Journal" called this mix of oversight and management responsibilities "murky". In an interview with the Journal, Rubin said: "I think I've been a very constructive part of the Citigroup environment." Separately, the "Journal" noted that Citigroup shareholders have suffered losses of more than 70 percent since Rubin joined the firm and that he encouraged changes that led the firm to the brink of collapse. In December 2008, investors filed a lawsuit contending that Citigroup executives, including Rubin, sold shares at inflated prices while concealing the firm's risks. A Citigroup spokesman said the lawsuit was without merit. Earlier, Rubin had also come in for some criticism for his actions on Citigroup's behalf during the 2001 collapse of energy giant Enron Corp., a major client of the bank. With the troubled Enron facing a credit ratings downgrade - a potentially disastrous development for the energy company's investors, the company itself and ultimately, its lenders - Rubin called a ranking Treasury Department official, unsuccessfully seeking the Bush Administration's help in forestalling the downgrade. Rubin later maintained that he had acted both as a Citigroup executive protecting his company's position and as a former Treasury official concerned about the impact that Enron's failure might have on the larger economy, brushing off the notion of any possible conflict of interest, and said that if faced with the same choice, he would do it again.