S&P 500 on winning streak as it enters strong season

The S&P 500 closed at a record high on Friday after rising 0.3 percent over the week.

The weekly gain was the S&P 500's eighth in a row, its longest weekly winning streak in four years.

Analysts at LPL Research think that stocks will continue to rise after the S&P 500 rose over 6 percent during the May to October period this year.

They noted that in the years when the six-month period from May to October was up at least 5 percent, the historically strong November to April period gained an average 9.2 percent compared to its usual 7 percent gain.

In contrast, Phil Streible, senior market strategist at RJO Futures, thinks that the winning streak may be coming to an end.

“I think you have to watch the retail sector from Black Friday on to the end of the year,” Streible told CNBC on Friday. “That could be what starts to show some of the cracks there in the foundation, and I think markets start to pull back.”

Meanwhile, other analysts are concerned with high market valuations.

Noting that the S&P 500's cyclically adjusted price-earnings ratio has risen above 30, Graham Hacche at the National Institute for Economic and Social ­Research said that “markets may have become increasingly vulnerable to shocks”.