What goes down must come up, right? Today, the Dow Jones jumped 378 points, or 5.8 percent, to close at 6926.49, its best day in three months. The surge, which also boosted the S&P 6.37 percent and the Nasdaq 7.07 percent, was spurred by Citigroup’s 25-percent gain after CEO Vikram Pandit reported the bank is having its best quarter since 2007. The bank jumped an astonishing 38 percent, while the other big banks—J.P. Morgan, Wells Fargo, and Bank of America—all surged at least 20 percent.