Apple (AAPL 0.63%) closed out the day up the day an impressive 7.2%, far outpacing the broader Nasdaq's 2% gains. Put in more impressive terms, the company added $35 billion to its market value in a day. This all coming on a day where there was little news about Apple itself. 

Instead, the focus shifted to broader economic concerns. Splashed front and center of almost every financial news site was talk of building optimism surrounding U.S. budget talks. Investors have come to fear the dreaded "fiscal cliff," in which spending cuts and tax increases kick in at the end of the year unless politicians can reach a compromise. Seeing why the fiscal cliff would be a major hit to companies is fairly obvious: Increased taxes will drain spending power for discretionary items like iPads and iPhones. Not only that, but the cumulative effects of those tax cuts and government spending cuts is projected to turn U.S. economic growth negative. 

Fears over the fiscal cliff have been a central component in the market's recent sell-off. With Apple having seen its own shares tumble about 25% since Sept. 21 -- far outpacing the Nasdaq's 10% loss -- today's market rally presented quite the one-day rebound. When markets turn after a sharp sell-off, the most beaten-down companies generally see the biggest gains. Should Apple investors celebrate today's gains, or keep a wary eye to continuing fiscal cliff worries? Let's take a deeper look. 

We've seen this rodeo before
The stand-off over the U.S. budget isn't a new situation. You may recall the gamesmanship played over raising the debt ceiling during the summer of 2011. That showdown led the S&P 500 to fall 17% in less than a month. Tech stocks were badly beaten down during the sell-off, with most the selling centered on tech companies levered to IT spending. As company executives pulled back spending targets in the face of uncertainty, IT budgets were the first to be cut back. That led big-name IT companies like Cisco to issue strikingly negative guidance. 

However, at the time, Apple largely avoided the steep market plunge. Its share price dipped far less than the general market in large part because -- in stark contrast with other tech stocks -- its own earnings during the debt standoff surpassed all expectations. Apple posted earnings of $7.79 on July 19, 2011, far surpassing Wall Street's expectations of $5.83 per share. While tech stocks around it imploded, Apple's bread and butter of consumer spending was still firing on all cylinders. Not only that, but it had the aura of invincibility around it, having posted its most impressive earnings thumping to date. 

Is this time different?
Flash forward to the fiscal-cliff standoff today, and much remains the same. Big IT companies are issuing worrying guidance as budgets look insecure. That's led to a selloff across technology. 

Yet this time, instead of coming off thumping earnings, Apple has instead missed earnings expectations in three of the past five quarters. Not only that, but as the company expands, it's more directly in the crosshairs of budget talks. While most of Apple's sales are still to consumers, its sales growth in businesses has been impressive in the past year. Between iPads finding buyers across almost every Fortune 500 company and the iPhone replacing Research In Motion (BB -2.09%) BlackBerrys in businesses and government agencies, Apple has seen its exposure increased to areas that would be most affected if the fiscal cliff isn't resolved. 

Not only that, but a U.S. slide back into a recession would have a very negative impact on the struggling global economy. A weak U.S. economy not only would put further strain on Europe as the continent works on its own debt woes, but the follow-on effect would be that developing countries like China would see even more pressure on their own sliding growth rates. Apple now sees 15% of its sales into Greater China and continues seeing phenomenal growth in the country. That's growth central to Apple's continuing gains in the coming years, but also growth that's endangered 

Beyond doom and gloom
There are pretty good reasons for not only Apple investors, but tech investors in general to be worried about the fiscal cliff and its near-term effects. While markets rallied today, the optimism largely came from comments from lawmakers stating their confidence that a deal will be finished before the end of the year. There's a large gap between the mere optimism over a deal and, you know, actually finding compromise and getting one done. 

This is by no means saying Apple is a bad investment. On the bright side, we saw a similar standoff that was averted last summer. Beyond that, Apple rallied hard today in part because there's little optimism priced into its shares. The company trades below general market P/E levels in spite of continued growth opportunities in both smartphones and tablets. Even if the fiscal cliff becomes a reality, Apple's huge  $120 billion war chest allows the company to continue investing while competitors wouldn't have much flexibility. 

However, it is a reminder to investors focused on the day-to-day ups and downs of Apple that rallies on political news are often short-lived and quickly reversed. If you think Apple's recent slide will be averted by a single day of "positive comments," remember that political standoffs are rarely resolved in a smooth fashion.