Citigroup, the nation’s largest bank, reported a staggering fourth-quarter loss of $9.83 billion on Tuesday and issued a sobering forecast that the housing market and the broader economy still had not bottomed out.

To shore up their financial condition, Citigroup and Merrill Lynch, which has also been rocked by the subprime mortgage debacle, both were forced again to go hat in hand for cash infusions from investors in the United States, Asia and the Middle East, for a combined total of nearly $19.1 billion.

Citigroup’s gloomy news will most likely amplify the anxiety of consumers and workers already concerned that the mortgage crisis could plunge the economy into a recession. Adding to worries, the government reported that retail sales in December declined for the first time since 2002.