The technical problem with buying stocks now

Stocks have managed to bounce nicely over the last two weeks, after a swift drop in late August. But the worst may not be over for stocks, says Oppenheimer technical analyst Ari Wald, whose examination of market seasonality suggests a cautious outlook.

"Seasonal trends remain very bearish for the next month," Wald said in a Tuesday "Trading Nation" segment. "September as a whole is one of the worst-performing months of the year for the stock market going back to 1950, and when you look into those numbers, September is even worse when the S&P ends August below its 200-day moving average," referring to an indicator that records the average of the prior 200 closing prices.

"When it's in a downtrend, when you have weakness going into September, markets tend to get even weaker," Wald said.

The technician suggests that the S&P 500, which opened Wednesday at 1,971, has resistance just overhead at 2,000, and could fall below 1,900 within the month.

However, trader Boris Schlossberg of BK Asset Management has a different take on the numbers.

"If you look seasonally past September, it's actually been a very good time to buy into October and November, when the market tends to rally over the last 10 years. So now might be a time to start accumulating into that potential rally," Schlossberg said Tuesday.

Read MoreStocks close down 1.4% despite global rally


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Trading Nation is a multimedia financial news program that shows investors and traders how to use the news of the day to their advantage. This is where experts from across the financial world – including macro strategists, technical analysts, stock-pickers, and traders who specialize in options, currencies, and fixed income – come together to find the best ways to capitalize on recent developments in the market. Trading Nation: Where headlines become opportunities.

Sara Eisen

Sara Eisen joined CNBC in December 2013 as a correspondent, focusing on the global consumer. She is co-anchor of the 10AM ET hour of CNBC's "Squawk on the Street" (M-F, 9AM-11AM ET), broadcast from Post 9 at the New York Stock Exchange.

In March 2018, Eisen was named co-anchor of CNBC's "Power Lunch" (M-F, 1PM-3PM ET), which broadcasts from CNBC Global Headquarters in Englewood Cliffs, N.J.

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