New York ? Disappointed by news of frail consumer spending, investors sold stocks sharply lower again Monday, pulling the Dow Jones industrials down by triple digits for the second straight session.

The downturn capped another dismal quarter on Wall Street, the worst for the Standard & Poor’s 500 index in 15 years.

“The level of investor anxiety has just reared up its ugly head again. It is just totally driven by uncertainty,” said Joseph Keating, chief investment officer at AmSouth Asset Management.

The Dow closed down 109.52, or 1.4 percent, at 7,591.93, having dropped 295 on Friday.

Monday marked the end of the third quarter, and the three major indexes recorded big losses. The S&P fell 17.6 percent, its worst quarterly loss since the fourth quarter of 1987 when it slid 23.3 percent. The S&P also ended its worst six-month period, down 29 percent, since 1974 when it dropped 32.4 percent in the second and third quarters.

The S&P stands at a five-year low, while the Dow, with a quarterly decline of 17.9 percent, is at a four-year low and the Nasdaq, down 19.9 percent, is at a six-year low.

On Monday, investors were irked by discouraging news about consumer spending, which accounts for two-thirds of the economy. First, the Commerce Department reported that consumers increased their spending in August by only 0.3 percent, falling short of expectations for a 0.5 percent pickup. News that incomes rose by 0.4 percent failed to ease investors’ disappointment about spending.

Investors also were let down by the Purchasing Management Association of Chicago, which reported that its index of area business activity fell to 48.1 in September. A reading below 50 indicates business is contracting, and this was the first such reading in seven months.