U.S. shares are set to edge up further on Wednesday, building on the gains made in the previous session when they posted the biggest rise in four months.

Treasury secretary Tim Geithner will hold a briefing at 1700 GMT (12 p.m. EDT) ahead of the weekend G-20 finance ministers and central bank governors meeting.

Also on Capitol Hill, Neel Kashkari, the interim assistant secretary of the Treasury for financial stability testifies on the Troubled Asset Relief Program (TARP).

Office supplies company Staples is expected to report lower fourth-quarter earnings as its U.S. small business customers grapple with the recession.

Apple Inc will take a third-quarter delivery of newly developed 10-inch touchscreens from Taiwan, a source said on Wednesday, amid talk the U.S. firm is developing a touch-screen PC.

Crude oil inventories fell slightly last week, according to a Reuters poll. Data is due at 1430 GMT (10:20 a.m. EDT).

New York prosecutors are investigating whether the early payment of bonuses at Merrill Lynch last year gave the bank's traders an incentive to mark down the value of their trading positions in the last days of December, the Financial Times said, citing people familiar with the probe.

Financials led a massive rally on Tuesday, with major indexes jumping off 12-year lows after Citigroup's chief executive, Vikram Pandit, stated in a memo to staff that the bank was profitable in the first two months of 2009.

The Dow Jones industrial average <.DJI> gained 5.8 percent; the Standard & Poor's 500 Index <.SPX> climbed 6.4 percent; the Nasdaq Composite Index <.IXIC> jumped 7.1 percent.

(Reporting by Brian Gorman; Editing by Greg Mahlich)