Earnings season isn't in full swing yet, but there's no doubt it's just around the corner. On Tuesday, Citigroup ( C) will start things off before the open. The report from the financial giant is expected to offer more insight into the extent of Citi's writedowns and possibly a restructuring plan that could include job cuts or a new investment. Following the close, another key company, and like Citi a component of the Dow Jones Industrial Average, chip titan Intel ( INTC), will report. Quarterly numbers are also expected from State Street ( STT), US Bancorp ( USB), Forest Labs ( FRX) and Linear Technology ( LLTC). The economic calendar will be rather full, featuring December retail sales and November business inventories from the Census Bureau, the producer price index from the Labor Department and two recaps of weekly retail sales, one from Redbook Research and the other from the International Council of Shopping Centers and UBS. Also, the Treasury Department will auction 10-year notes, and the New York Empire State index is due. On TheStreet.com, Ted Reed will explain what airline mergers could mean for existing code-shares and mega-alliances such as Oneworld and Skyteam, and Chuck Marvin will discuss the five best stocks in a hard-to-like sector -- ethanol.