Traders working on the floor of the New York Stock Exchange this week have faced ups and downs in the market. For the week, the Dow ended down 193.88, or 1.51 percent, at 12,606.30.

New York ? Wall Street plunged again Friday amid renewed fears that the financial sector’s troubles with bad credit won’t end soon and that some consumers are buckling under the weight of a slowing economy. The major indexes each lost more than 1 percent, including the Dow Jones industrials, which finished down nearly 250 points.

The arrival of quarterly earnings reports has investors worried about how banks and brokerages have fared after suffering losses in the collapse of the subprime mortgage market. Traders appeared to grow more pessimistic ahead of reports due next week from the nation’s biggest financial institutions. Merrill Lynch & Co., Citigroup Inc. and JPMorgan Chase & Co. are slated to weigh in next week.

Adding to investors’ unease, Merrill Lynch might take a $15 billion hit from its exposure to soured subprime mortgage investments, according to The New York Times. The nation’s largest brokerage is also said to be seeking another capital infusion to help shore up its balance sheet.

Investors also grew nervous after American Express Corp. warned that slower spending and more delinquencies on credit card payments will hamper profit throughout 2008. A profit warning from Tiffany & Co. added to Wall Street’s unease about the fortitude of the consumer.

“When Amex comes out and says that some of their well-to-do cardholders are having problems making payments that’s just not good news,” said Brandon Thomas, chief investment officer of Portfolio Management Consultants, the investment arm of Envestnet Asset Management.

Friday’s session revealed the extent of misgivings about Wall Street’s efforts to sew up its troubles. Bank of America Corp. agreed Friday to buy Countrywide Financial Corp. for $4 billion, a deal that rescues the country’s largest mortgage lender but pays less than the company’s market value.

The agreement comes after word of the move Thursday and just months after BofA invested $2 billion in Countrywide. Some investors apparently hoped Countrywide would fetch a premium, though some observers said a tie-up was a better alternative than bankruptcy, rumors of which dogged the company during the week.

Michael Church, portfolio manager at Church Capital Management, said news from the financials is weighing on Wall Street, although he said investors shouldn’t be surprised by the extent of the troubles.

“The financials are going to continue to be a problem,” he said.

The Dow Jones industrial average ended the week down 193.88, or 1.51 percent, at 12,606.30. The Standard & Poor’s 500 index finished down 10.60, or 0.75 percent, at 1,401.02. The Nasdaq composite index ended down 64.71, or 2.58 percent, at 2,439.94.