Goldman Sachs analyst William Tanona today helped tank Citigroup’s stock, releasing a report that said the financial services provider could write off as much as $15 billion during the next two quarters — and said that Citigroup may need to cut its divident in order to preserve liquidity. As a result, Citigroup’s stock dropped nearly 6 percent to close at $32.00. From the Associated Press:

“The lack of leadership at this point in Citi’s storied history could not have come at a worse time,” wrote Tanona in a research note. “With deteriorating consumer and housing metrics, Citigroup is facing mounting pressure across many businesses.” … Furthermore, if the housing market keeps dragging on consumer spending, Citi’s credit card and retail banking businesses could weaken, Tanona said… Tanona also cut his share price target for Citi to $33, and reduced earnings estimates for the entire large-cap investment banking sector through 2009. He said the credit markets “remain extraordinarily challenging,” and that Goldman’s financial services research team sees home prices falling well into 2008.

Citigroup recently reported $3 billion in losses within its fixed-income business for the third quarter, and said that it expected further deterioration during the fourth quarter.