NEW YORK(CNN/Money) - A worse-than-expected retail sales report and a revenue warning from telecom gear maker Lucent Technologies pushed U.S. stocks lower Thursday morning as major indexes were unable to sustain the previous session's late-day rally.

Around 10:50 a.m. ET, the Dow Jones industrial average fell 81.68 to 9,536.03. The Nasdaq composite index lost 18.23 to 1,500.89, while the Standard & Poor's 500 index was 7.61 lower at 1,012.65.

May retail sales fell 0.9 percent, far more than the 0.2 percent drop economists surveyed by Briefing.com were expecting. In April, retail sales grew 1.2 percent. Excluding the autos component of the reading, May sales fell 0.4 percent.

"The retail numbers were really weak and the markets responded," said Brian Finnerty, managing director at Melhado, Flynn & Associates. "This is the kind of market where any glitch, any chink in the armor can set us off."

The decline may reflect a drop in consumer sentiment, but may also reflect another kind of drop -- raindrops that kept customers out of stores.

"We knew that it was a wet month and that rain tends to keep people away from shopping, so I thing a large part of this is actually a weather story," Bill Cheney, chief economist at John Hancock Financial Services, told CNNfn's CNNmoney Morning.

Among the stocks hurting the Dow was the No. 1 retailer, Wal-Mart Stores (WMT: down $1.30 to $57.00, Research, Estimates).

Another economic measure, the Producer Price Index, a measure of inflation at the wholesale level, declined 0.4 percent last month instead of the 0.1 percent rise economists expected; prices fell 0.2 percent in April. Excluding food and energy costs, the "core" index was unchanged.

In addition, the number of Americans filing new jobless claims rose to 390,000 from 384,000 in the previous week, below the consensus of economists and the key 400,000 level which is seen as a symbol of a weak economy.

In corporate news, telephone equipment maker Lucent (LU: down $0.31 to $2.64, Research, Estimates) warned that fiscal third-quarter revenue will miss expectations due to continued weakness in the sector.

The Lucent weakness spilled over into a number of other telecom and networking companies, including Cisco Systems (CSCO: down $0.52 to $14.77, Research, Estimates) and Ciena (CIEN: up $0.04 to $4.32, Research, Estimates), which was also under pressure after Merrill Lynch reiterated its "reduce/sell" rating on the stock, saying that it still has downside risk.

On an up note, troubled conglomerate Tyco International (TYC: up $2.95 to $13.10, Research, Estimates) received upgrades from both Merrill Lynch and J.P. Morgan. However, a published report said that the Securities and Exchange Commission has reopened a 1999 probe into Tyco's accounting and acquisition practices. On Wednesday, the company moved closer to getting an SEC OK for an initial public offering of its CIT Group financial services unit.

Shares of Dow component and computer hardware leader IBM (IBM: up $1.40 to $76.05, Research, Estimates) rose after a pair of analysts issued positive comments. S.G. Cowen raised its 2002 and 2003 estimates on the stock, saying it looks conspicuously undervalued. UBS Warburg said that IBM's restructuring actions are eliminating businesses that have been a drag on the company's earnings outlook and that Big Blue is enhancing its competitiveness.

Treasurys rose sharply in early trade, pushing the yield on the 10-year note down to 4.90 percent.

European markets were mixed in afternoon trade, while Asian markets ended lower. The dollar was weaker versus the euro and the yen. Light crude oil futures rose 37 cents to $24.23.

Market breadth was negative. On the New York Stock Exchange, losers beat winners by more than 9-to-5 as 256 million shares changed hands. On the Nasdaq, decliners topped advancers 7-to-4 as 322 million shares traded.