NEW YORK (CNN/Money) - U.S. stocks fell Wednesday on profit taking in technology and in response to a purported new Osama bin Laden tape, on the eve of the two-year anniversary of the terrorist attacks of Sept. 11.

Major stocks markets and the NYMEX -- where energy and metals futures trade -- will observe the anniversary with four separate minute-long moments of silence, at 8:46 a.m., 9:03 a.m., 9:59 a.m., and 10:29 a.m. ET Thursday. The times will reflect when two planes hijacked by terrorists crashed into the World Trade Center's two towers and when the two towers collapsed.

However, trading will begin and end at normal hours.

Stocks slid sharply Wednesday on a bout of profit taking but suffered a steeper setback after 2 p.m. ET after reports that Arabic news network Al Jazeera had aired what it said was a new videotape of Osama bin Laden and his top deputy, although authorities have not been able to verify its authenticity. Yet, the hint of it was enough to unnerve investors.

Trade Thursday is expected to be fairly subdued, in light of the anniversary.

Though most analysts say the events of Sept. 11 have not factored into stock trade in recent weeks, the ongoing impact of the day has continued to weigh on financial markets. Additionally, fears about terrorism persist, particularly amid the ongoing U.S. involvement in Iraq and Afghanistan.

In terms of other market-influencing events, Thursday brings a lot of economic news and some from corporate America as well.

After the close of trade Wednesday, Adobe Systems (ADBE: down $1.64 to $36.39, Research, Estimates) reported quarterly earnings of 27 cents per share, 2 cents better than analysts expected and a nickel better than a year earlier. The company cited growth in its ePaper business as the reason for the results.

Additionally, Johnson & Johnson (JNJ: up $0.79 to $52.04, Research, Estimates) said late Wednesday that results in its recent trials in Canada and Europe of its treatment for clogged heart arteries showed better results than similar trials in the U.S.

Due before the opening bell, the report on new weekly claims for unemployment is expected to show a decline to 400,000 from 413,000 the previous week, according to Reuters research.

In addition, figures on the July trade balance are due in the pre-market. The deficit is expected to have grown to $40.5 billion from $39.5 billion last month, according to Reuters research.

Reports are also due on import and export prices in August.

The tech-heavy Nasdaq composite (down 49.62 to 1823.81, Charts) lost 2.6 percent, its biggest one-day percentage slide in a month. The Standard & Poor's 500 (down 12.25 to 1010.92, Charts) index lost 1.2 percent and the Dow Jones industrial average (down 86.74 to 9420.46, Charts) fell 0.9 percent.

Stocks rallied sharply during the last few weeks as investors cheered the increasing number of positive economic reports -- minus labor market statistics -- and signs that the third quarter should be strong. Bullish analyst calls on the technology sector in the last week added to the gains.

But after three weeks of advances for the Nasdaq and the S&P 500, and five "up" weeks for the Dow, investors opted to make some money on the rally. The purported reason for the consolidation Wednesday -- the second such day in a row -- was the lackluster outlook offered by a few in the chip sector, in particular Texas Instruments.

"Texas Instruments' conference call left people pretty cold," said Robert Philips, chief investment officer at Walnut Asset Management. "That broke the momentum of that group and has spilled over into other tech stocks."

Technical factors also came into play, some analysts said, as the S&P 500 broke through the top of its three-month trading range.

In its mid-quarter update after the close of trade Tuesday, Texas Instruments (TXN: down $1.90 to $23.42, Research, Estimates) said its third-quarter earnings will come in at the higher end of its previous forecast, due to improved demand for some of its products. But investors' reaction to the news was to sell the stock, driving it 7.4 percent lower, amid disappointment that the company failed to give a more aggressively positive outlook.

Chip gear maker Xilinx (XLNX: down $1.81 to $30.29, Research, Estimates) was given the same cold shoulder after it reaffirmed its quarterly forecast.

Investors who are already expecting good news may not be so willing to reward companies that meet, but don't exceed, estimates, said Brian Finnerty, managing director at Melhado Flynn & Associates, pointing to a trend that has been emerging more and more over the last few weeks.

"Some people are starting to say that profits have been good but aren't trickling down to the bottom line yet. But I think this [perception] will be a short-lived phenomenon," Finnerty said. "You're going to start seeing more companies whose profits are showing real growth."

Until then, investors may continue to take profits on the techs that have played leader of late, particularly on the heels of negative company news and analyst calls.

SoundView Technology's downgrade of chipmaker Micron Technology (MU: down $1.35 to $13.35, Research, Estimates) to "neutral" from "outperform," citing worries about demand for its products in Asian markets, sent the stock down 9.2 percent.

Micron's slide, combined with TI, put some heavy selling pressure on techs across the board. Although Micron and TI both trade on the New York Stock Exchange, they have an impact on other chip stocks on the tech-fueled Nasdaq. Intel (INTC: down $1.13 to $27.66, Research, Estimates) fell 3.9 percent in active trade. The Philadelphia Semiconductor (down 24.84 to 441.89, Charts) index, or the Soxx, lost 5.3 percent.

Telecom and networking shares continued to bleed. Nokia (NOK: down $0.61 to $15.39, Research, Estimates) lost another 3.8 percent Wednesday, on top of the more than 6 percent the stock shed Tuesday after the Finnish telecom equipment maker said the weak U.S. dollar and increased competition would stifle revenue growth at its main unit.

Nortel Networks (NT: down $0.15 to $3.95, Research, Estimates) lost 3.4 percent Wednesday after losing almost 10 percent Tuesday, due to the domino effect of Nokia's slide. Nortel also had its own problems Wednesday. Smith Barney downgraded the stock to "under weight" from "in line" and trimmed its price target, saying that the stock is overpriced.

Smith Barney also cut Juniper Networks (JNPR: down $0.94 to $16.55, Research, Estimates) to "in line" from "outperform" and trimmed its price target, saying the company is well-managed but the stock is pricey. Shares fell 5.4 percent.

In other tech news, Sun Microsystems (SUNW: down $0.31 to $3.80, Research, Estimates) lost 7.5 percent, one session after saying its co-founder and chief scientist was leaving the company. The stock topped the Nasdaq's most-active list.

Dow stock Honeywell (HON: down $1.02 to $28.09, Research, Estimates) fell 3.5 percent and was the blue-chip average's biggest decliner after the company's chief financial officer made some bearish comments at a Morgan Stanley industrials conference late Tuesday, Reuters reports. The company's CFO said that while July provided some encouragement, orders had slipped in August.

On the upside, Xybernaut (XYBR: up $0.17 to $1.25, Research, Estimates) rallied almost 15.7 percent in unusually active trade, after the maker of wearable and mobile computers received a $1.63 million order from the U.S. Department of Defense to design a number of products.

Market breadth was decidedly negative. Two stocks fell for every one that rose on the New York Stock Exchange, where volume was almost 1.5 billion shares. Almost three stocks fell for every one that rose on the Nasdaq, where 1.96 billion shares changed hands.

Treasury prices rallied, pushing the 10-year note yield down to 4.27 percent, as its price gained 22/32 of a point. The dollar was fractionally higher versus the euro and lower against the yen.

NYMEX light sweet crude oil futures added 17 cents to settle at $29.35 a barrel. COMEX gold fell $1.70 to settle at $381.10 an ounce.