NEW YORK (Reuters) - Wall Street could get a quick boost this week from signs of President-elect Barack Obama's economic stimulus plan, but concerns about the long-term outlook and the fate of Citigroup will still weigh on investors.

The holiday-shortened week begins with Obama set to introduce his economic team today, including Timothy Geithner, 47, president of the New York Federal Reserve Bank, as his secretary of the Treasury.

The week will finish with the first key indication of how much consumers are willing to spend this holiday season.

US stock prices, pummelled for most of last week, rallied more than six percent on Friday after word first leaked out that Geithner might take the helm at Treasury.

Investors will be looking to Obama and Geithner for signals on what they will do to stem the economic crisis.

US Sen. Charles Schumer, a New York Democrat, put the stimulus plan figure at between $500 billion and $700 billion, and an Obama aide hinted that a campaign promise to repeal tax cuts for the wealthy might be delayed.

"I think it will help the market on Monday, but I think it will be very short-term help," said Michael Pento, senior market strategist at Delta Global Advisors. "You can stimulate the economy in the short run by a temporary adrenalin stimulus and a steroid shot of deficits, but in the long run it's extremely deadly."

Obama on Saturday called for a two-year economic stimulus package that would include middle-class tax cuts and spending on projects like roads and bridges. He said he wants it soon after taking office January 20, although he did not put a value on the plan.

Some market watchers said attempts by the government to stave off a deep recession might only delay a further, painful realignment of markets with economic reality.

"The politicians are trying to blunt the full impact of a market correction that we have seen in action for some time now," said Peter Kenny, managing director at Knight Equity Markets. "The bottom line is this market is going to correct with or without a stimulus package."

In the past week, markets erased more than a decade of gains as banks, led by Citigroup, touched new lows and worries mounted about the likelihood of a bailout for automakers. Stocks also reeled from a slew of negative data that put US new jobless claims at a 16-year high. Further stock gains building on Friday's rally could help soften November's losses. It had been on course to be one of the worst months for stocks on record.

"The market is still going to remain concerned regarding the state of the financials and the huge meltdown in the banks," Fred Dickson, market strategist of DA Davidson & Co in Lake Oswego, Oregon, said late last week. Key economic indicators on tap for this week include existing-home sales for October, consumer sentiment and confidence, and weekly US jobless claims data.

But market watchers will hone in on Citigroup over the weekend for any developments as to the future of the bank, the second-largest in the US by assets.

Citigroup's board met on Friday to discuss the bank's options, according to a person familiar with the matter. The bank could sell parts of the company, or merge with another institution.

The meeting came amid reports that directors were looking to replace Citigroup's chief executive, Vikram Pandit, and Citigroup was cutting additional staff in Japan.

"Hopefully it'll be a positive news story, whether it be a sale of the company, a restructuring, a new management — the market will take anything at this point," said Joe Saluzzi, co-manager of trading at Themis Trading in Chatham, New Jersey.

Citigroup's shares shed 20 percent on Friday to close at $3.77 — a loss of around 60 percent for the week. In after-hours trading on Friday, Citi shares rose 6.6 percent.

For the week, the Dow lost 5.3 percent, the S&P 500 fell 8.4 percent, and the Nasdaq lost 8.8 percent, even after all three indexes surged more than five percent on Friday.

The dismal week capped off a historic November that is quickly becoming one of the worst months for US stocks since October 1987. Through Friday, the S&P is down more than 17 percent for the month of November, the Dow is off nearly 14 percent, and Nasdaq is nearly 20 percent lower.

Light volume owing to the Thanksgiving Day holiday on Thursday and a half day on Friday will almost certainly exacerbate volatility, as retailers take the spotlight in the latter half of the week. Wall Street will look to Black Friday, the day after Thanksgiving, which kicks off the holiday shopping season and is traditionally the biggest shopping day of the year, for a gauge of consumer spending.

But outlooks from major retailers suggest this could be one of the worst holiday shopping seasons in years.