While Apple ( AAPL) shined, emerging-market stocks had a bad day Tuesday, thanks largely to Venezuela President Hugo Chavez's plans to nationalize his country's telecom and power industries.

But a bad day shouldn't be extrapolated to mean the global economy is suddenly weak, or that risk appetite is waning on a large scale. The plunge in emerging markets reminded many traders of late April and early May 2006, when emerging market stocks sold off ahead of U.S. stocks.

Indeed, an emerging market selloff may well be the crack in the rally that gives investors reason to kick off a correction in the U.S. stock market. But it doesn't necessarily foreshadow a weak economy or impending disaster.

The iShares MSCI Emerging Markets Index slid 2.3% Tuesday; Brazil's Bovespa fell 2%; Mexico's benchmark IPC Index lost 1.8%; and Venezuela's Caracas Stock Exchange Index fell 30% in 15 minutes of trading. Emerging-market weakness wasn't contained to South America only. The iShares FTSE Xinhua China 25 Index fell 4.3% on the day, while Russia's major index slid 6.4%.

Some investors likewise lament the overall decline in commodities lately (though natural gas, heating oil, copper and gold rose Tuesday) as reason to worry about the global economy. Some traders have attributed some of the emerging-market selling to the commodity weakness, and warn of contagion.

"The adjustment in the markets for the drop in commodities prices will entail some pain and market instability," writes Tony Crescenzi, chief fixed-income strategist at Miller Tabak, and contributor to RealMoney.com.

While a correction in U.S. stocks may be at hand, it is unlikely going to be because a hard landing for the economy is suddenly approaching, or because liquidity that fueled risk appetite suddenly disappeared. If these scenarios were true, Crescenzi notes, risk premiums on corporate bonds, inflation expectations implied by inflation-protected Treasuries, and other liquidity-sensitive assets would reveal more instability. So far they do not.

Also, recent strong economic data pointing to healthy consumption, employment and a possible trough in the housing market contradict worries that the global economy is headed to the abyss. Lastly, the rally in tech stocks suggests that an economic plunge would be the wrong read on commodity and emerging-market volatility.

To wit, Apple's MacWorld debut of its sleek (and expensive) iPhone -- its shares soared 8.3%, providing a boost to major averages, which spent another day fluctuating between red and green before ending mixed. The Dow Jones Industrial Average closed down 0.06% at 12,416.60, while the S&P 500 slid 0.05% to close at 1412.11; the Nasdaq Composite gained 0.23% to close at 2443.83.

Technology is the theme of the year so far, as investors bet that companies with large pools of cash will finally start to upgrade their systems, particularly as Microsoft's ( MSFT) new Window's operating system, Vista, is now on the market. A growth-dependent sector like technology wouldn't be in the limelight if investors or companies were really all that worried about the global economy.

Although the iPhone threat (perceived or actual) weighed on shares of Research In Motion ( RIMM), Palm ( PALM) and major cell-phone providers, other technology companies continued to do well Tuesday. Shares of Dell ( DELL), IBM ( IBM) and Hewlett Packard ( HPQ) added between 0.6% and 2.5% on the day.

Earnings season kicked off on a strong note after the close Tuesday, as aluminum producer Alcoa ( AA) reported a stronger-than-expected fourth quarter. Shares of the company were gaining 5% in after-hours trading.

The tech strength offset more weakness in the energy sector as oil fell another 0.5%, or 28 cents, to close at $55.81 per barrel. The price had plunged as much as $2 per barrel intraday. Oil stocks fell in kind. Shares of Exxon Mobil ( XOM), BP ( BP), and Chevron ( CVX) dropped between 0.8% and 2.9% on the day.

It seems difficult for investors to decide if oil-price weakness is good or bad for the U.S. economy. Less inflation pressure is good, but less demand is scary.

The truth of the decline may well be in the hands of speculators, who are taking off commodities bets they've had in place for months.

Merrill Lynch's Richard Bernstein notes that speculation "does appear to be starting to calm down, but only just a bit." His models show commodities speculation peaked in September 2006, when listed commodities were priced at levels "more than 60% above what could be justified by fundamentals," he writes.

That has moved down to 43%, Bernstein says. Long-term investors should stick with their investments in commodities for diversification purposes, he continues, but warns that investors looking for another big win in 2007 "might be disappointed."

In keeping with TSC's editorial policy, Rappaport doesn't own or short individual stocks. She also doesn't invest in hedge funds or other private investment partnerships. She appreciates your feedback. Click here to send her an email.

More from Opinion

Week of the Women From Finance to Fast Food

Week of the Women From Finance to Fast Food

Tuesday Turnaround: Micron, Autonomous Driving, and J.C. Penney

Tuesday Turnaround: Micron, Autonomous Driving, and J.C. Penney

Cable Stock Investors Should Keep an Eye On Wireless Broadband's Rise

Cable Stock Investors Should Keep an Eye On Wireless Broadband's Rise

Trump Blinks on China Trade War That's Looking Harder to Win

Trump Blinks on China Trade War That's Looking Harder to Win

Monday Madness: GE, China, and Micron

Monday Madness: GE, China, and Micron