NEW YORK — Wall Street had its worst day in more than four months yesterday as the dollar weakened and concerns about the strength of the retail industry arose following a rare sales decline at Wal-Mart Stores Inc. The Dow Jones industrials fell 158 points.

Investors were uneasy after the dollar fell for the fifth straight day and after Wal-Mart, the world's largest retailer, reported a 0.1 percent drop in same-store sales, from stores open at least a year. Same-store sales are the industry standard for assessing a retailer's strength, and while overall retail sales appeared strong last weekend, Wal-Mart's first deficit in a decade raised concerns about the strength of consumer spending during the holiday season.

"There is now significant concern that the holiday retail season is going to underperform," said Gregory Miller, chief economist at SunTrust Banks. "Traffic doesn't necessarily translate into profits," he said, referring to reports of crowded stores over the weekend.

As the dollar's slide continued, it hit a 20-month low against the euro, though it did for a time move higher against the Japanese yen. The dollar's fall raised concerns that foreign investors were sensing weakness in the U.S. economy and would pull some of their investments from U.S. markets.

Beyond the weak dollar and news from Wal-Mart, some retrenchment was to be expected as investors seek to preserve their profits after stocks have soared the past two months.

The Dow fell 158.46, or 1.29 percent, to 12,121.71, as 27 of the index's 30 blue chip stocks fell. It was the Dow's biggest slide since a string of triple-digit declines in mid-July that followed disappointing profit reports and a spike in oil prices amid tensions with Iran and North Korea.

Broader stock indicators also dropped sharply yesterday. The Standard & Poor's 500 index fell 19.05, or 1.36 percent, to 1,381.90, and the Nasdaq composite index slid 54.34, or 2.21 percent, to 2,405.92.

Bonds rose, with the yield on the benchmark 10-year Treasury note falling to 4.53 percent, from 4.55 percent late Friday. Gold prices rose.

Light, sweet crude was up $1.08 at $60.32 a barrel on the New York Mercantile Exchange. Crude prices gained ground after an attack on an oil facility in Iraq and comments by Saudi Arabia's oil minister that OPEC could consider further production cuts next month.

Investors examining retail reports tried to determine whether an increase in traffic at stores would translate to higher profits for retailers. Consumer spending accounts for two-thirds of all economic activity, and Wall Street is concerned that weak spending would prevent the slowing economy from achieving a soft landing.

ShopperTrak RTC, which compiles sales data, estimates sales rose 6 percent on Black Friday from a year earlier.

Regardless of the pace of retail sales, however, stocks have posted strong gains in October and November, making yesterday's retreat unsurprising.

Miller said he remained concerned that the overall economy might be weaker than some investors had believed when they sent stocks higher in recent months. The Dow has closed at record levels 18 times since the beginning of October.

He also questioned whether retailers have run the risk of hurting profit margins by offering steep discounts to lure shoppers during an increasingly competitive Black Friday.

"The American consumer now expects that the holiday season isn't just a time to spend a lot of money but a time to get some bargains."

Wal-Mart fell $1.29, or 2.7 percent, to $46.61 following its report, while some retailers moved higher following reports of strong traffic in stores over the weekend. Lowe's Cos. rose 40 cents to $1.33.

The Russell 2000 index of smaller companies was down 20.18, or 2.55 percent, to 772.10.

Declining issues outnumbered advancers by about 4 to 1 on the New York Stock Exchange, where volume came to 1.6 billion shares.

Overseas, Japan's Nikkei stock average closed up 0.96 percent. Britain's FTSE 100 closed down 1.18 percent, Germany's DAX index fell 1.77 percent and France's CAC-40 was down 1.50 percent.