Nov. 3 (Bloomberg) -- The Standard & Poor’s 500 Index may extend its retreat from a one-year high last month to 12 percent, according to Oppenheimer & Co.

The benchmark for U.S. equity may drop to its average close of the past 150 days, said Carter Worth, Oppenheimer’s chief market technician. That level, at about 963 points, represents a 7.6 percent decline from yesterday’s close of 1,042.88 and a 12 percent retreat from the index’s one-year high on Oct. 19, according to Bloomberg data.

The biggest advance in U.S. equities since the Great Depression has stalled on speculation that the seven-month rally outpaced prospects for an economic recovery. The S&P 500 dropped 4 percent last week, falling the most since May and closing below its 50-day average for the first time since July, after reports showed new home sales missed economists’ forecasts and consumer spending declined.

“The market is struggling now at the down trendline in effect since the all-time highs of October 2007,” Worth wrote in a note to clients dated yesterday. “For those looking for longs, sit tight for a session or two. There is nothing to be lost, we believe, by postponing all new buying.”

On six occasions during its 62 percent surge from a 12-year low on March 9, the S&P 500’s intraday low exceeded the previous day’s intraday high, leaving so-called gaps on the benchmark’s graph. The index has filled three such gaps, falling below the previous intraday high. A pullback to the 963 level would fill up another and leave two more to close. The lowest gap incurred at a level of 813.62.

Almost all index gaps are eventually filled, said Worth, ranked third among analysts who study price charts in Institutional Investor magazine’s 2009 survey.

To contact the reporter on this story: Lu Wang in New York at lwang8@bloomberg.net.

Last Updated: November 3, 2009 15:45 EST