Goldman Sachs earnings almost tripled in the fourth quarter, handily beating analysts' estimates, as investment banking revenues surged. The investment bank earned $2.83 billion after paying preferred dividends, compared with $978 million a year earlier. The bank's debt underwriting business profited from a rally in bonds and a surge in demand for debt securities. Goldman's debt underwriting business earned $1.96 billion in revenues for the year, its second-best annual performance and the highest since 2007. "While economic conditions remained challenging for much of the last year, the strengths of our business model and client franchise, coupled with our focus on disciplined management, delivered solid performance for our shareholders," Goldman's CEO Lloyd Blankfein said in a statement Wednesday. The bank's compensation cost rose 6% to $12.94 billion for 2012. The bank also reduced its headcount by 3% to 32,400. That means that the average employee at the bank earns almost $400,000 a year. Goldman differs from other big U.S. banks because it deals almost exclusively with institutions, rather than consumers. Its clients are usually mutual funds, international corporations, other banks and similar firms. Revenue for the fourth quarter rose to $9.24 billion, 53% higher than in the same period a year ago, beating analysts' estimates of $7.97 billion. Goldman earned $5.60 on a per-share basis, compared with the average analysts forecast of $3.71, according to data provider FactSet. The banks stock gained $2.87, or 2.1%, to $138.46 in pre-market trading.