On the first full day of trading since the Thanksgiving holiday, fiscal-cliff jitters returned to the markets as Congress reconvened on Capitol Hill to debate the looming issue. Starting the day above 13,000, the Dow Jones Industrial Average (DJINDICES:^DJI) slid 42 points, or 0.33%, to close at 12,967. 

Hewlett-Packard (NYSE:HPQ) far outpaced the rest of the Dow, tacking on 2.5%. Shares have rebounded modestly since the company's steep 12% stumble last Monday, when the company announced it will take an $8.8 billion writedown because of its Autonomy acquisition last year. Twenty-two of the Dow's 30 components lost ground today, and Coca-Cola (NYSE:KO) led all laggards, shaving 1.5% off its market cap. The iconic soda maker is up slightly more than the index as a whole so far in 2012, trading 6.8% higher. The Dow is up 6.1% on the year. 

Knight Capital Group (NYSE:KCG) saw a lot of action today, and the financial services firm's shares jumped more than 13% on rumors that the company may sell its market-making unit. You may recall Knight Capital from the headlines earlier this year, when "glitches" caused more than $400 million in losses. Investors unsurprisingly bid up the stock today in hopes that the unit responsible for those losses will be pawned off.

Tech giants Facebook (NASDAQ:FB) and Apple (NASDAQ:AAPL) highlighted the tech sector, helping to drive the Nasdaq (NASDAQ:NDAQ) higher, gaining 8.1% and 3.2%, respectively. Facebook was buoyed by a bullish analyst who predicted the social networking company will hit nearly $7 billion in revenues in 2013, a figure 9% higher than average estimates. Apple was also the beneficiary of a newly positive outlook, as Citigroup gave shares of the Cupertino-based behemoth a $675 target price and a "buy" rating. Apple investors are keeping their eyes on holiday sales numbers, which could be a major catalyst for the company if they exceed estimates.

John Divine owns shares of Apple. You can follow him on Twitter, @divinebizkid, and on Motley Fool CAPS, @TMFDivine.

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