Stocks fold in last half-hour of trading

— -- Stocks fell Wednesday and failed to stretch their gains from the day before as investors continued to struggle with the significance of the subprime mortgage mess and volatile trading.

After being up most of the day, stocks succumbed to strong selling pressure in the last half-hour of trading. The Dow Jones industrial average sank 76.08 points to 13,231.01, erasing a portion of its 320-point gain Tuesday.

It was a similar story for the Standard & Poor's 500 index, which faltered 10.47 points to 1470.58 in the final portion of the trading day. And the Nasdaq composite index also lost 29.33 points to 2644.32.

"We faded fast at the close," says Andy Brooks, trader at T. Rowe Price. "It was a dramatic reversal."

There was news regarding write-downs of mortgage securities, including from Bear Stearns bscearlier in the day. But, the selling came so fast and late, indicating it was likely caused by large investors executing automated trades to move from stocks into another asset class, such as bonds, Brooks says.

Even after the day's losses, though, the major market indexes remain in the black for the year. The Dow is up 6.2%, the S&P 500 has gained 3.7%, and the Nasdaq composite index has risen 9.5%.

A big worry that's also plaguing investors is inflation, says Peter Cardillo of Avalon Partners. Prices at a wholesale level rose slightly in October, the Labor Department reported. Inflation fears only intensified with oil prices rising $2.92 a barrel to $94.09.

"The market remains very fragile," Cardillo says.

Highlights:

Bear Stearns gained $2.40 to $103.27 on the hope the company is working through its exposure to subprime mortgage investments. Bear Stearns' chief financial officer said it will write down $1.2 billion in debt.

•United Rentals urifell $10.51 to $23.50 after the industrial equipment rental firm extended its timetable for a refinancing until Friday. Reuters reported the move is a sign the offer by leveraged buyout firm Cerberus may be withdrawn. Cerberus is having trouble raising money from the debt markets to finance the buyout, Reuters says.

•Greater Community Bancorpgfls, a regional bank in New Jersey, jumped $5.80 to $20.20. Rival Oritani Financial orit is buying it for $21.40 a share. Oritani shares fell $2.23 to $14.84.

•Daktronicsdakt, maker of big screens for sports arenas, fell $8.68 to $19.89. It reported 10% lower quarterly profit.