The companies that reported earnings before the markets opened on Tuesday are: Citigroup, Forest Laboratories, Comerica, Delta Air Lines and TD Ameritrade.

Citigroup (C) reported a fourth consecutive profitable quarter. The company posted fourth quarter profit $1.3 billion or 4 cents a share compared with a loss of $7.6 billion or 33 cents a share in the year-ago quarter. Profit fell 40 percent from the prior quarter. Citigroup revenue was $18.4 billion and included negative CVA of $1.1 billion. Excluding CVA, revenue of $19.5 billion fell 6 percent from the prior quarter, mainly driven by lower Securities and Banking revenues, it said. Citigroup said total provisions for credit losses and for benefits and claims of $4.8 billion fell 18 percent sequentially to the lowest level since the second quarter of 2007.

Forest Laboratories (FRX) posted third quarter reported earnings per share of $1.11 compared with $0.69 last year. Quarterly earnings included a charge of 23 cents a share for a new product licensing fee. Adjusted non-GAAP earnings per share increased to $1.34 from $0.97. Net sales rose 6.7 percent to $1.06 billion. The company said it now expects that earnings per share for the fiscal year ending March 31, 2011 will be in the range of $4.20 to $4.30, excluding charges.

Comerica (CMA) swung to fourth quarter profit of $0.53 a share from loss of $0.42 a share last year. Fourth quarter net income included a provision for loan losses of $57 million, compared to $256 million in the same period of last year.

Sterling Bancshares (SBIB), which agreed to be bought by Comerica in a stock deal, reported quarterly earnings per share of 2 cents, flat with last year.

U.S. carrier Delta Air Lines (DAL)  reported fourth quarter net income, excluding items, of $158 million or $0.19 a share, compared with a loss of $225 million a year earlier. Delta's GAAP net income was $19 million or 2 cents for the quarter versus $25 million or 3 cents last year. Revenue rose 14 percent to $7.79 billion. The company said it expects to maintain its first quarter margins year over year despite more than $350 million in higher costs from the recent steep run-up in fuel prices.

TD Ameritrade Holding Corp. (AMTD) posted first quarter profit of $145 million or 25 cents a share, compared with $136 million or 23 cents in the year-ago quarter. Net revenue was $656 million, 51 percent of which were asset-based, up from $624 million last year. The company reported net new client assets of $9.7 billion, up 11 percent.

McMoRan Exploration Co. (MMR) posted a net loss applicable to common stock of $77.0 million or $0.75 per share for the fourth quarter, compared with a net loss applicable to common stock of $9.5 million or $0.11 per share for the fourth quarter a year-ago. McMoRan’s fourth-quarter 2010 oil and gas revenue was $95.1 million, compared with $128.0 million last year.