Consumer discretionary ETFs have consistently outperformed the S&P 500 the past few years as retailers and consumers recover after the financial crisis.

For example, Consumer Discretionary Select Sector SPDR (NYSEArca: XLY) was making new all-time highs back in 2011 well before the S&P 500 and other major U.S. equity benchmarks.

However, the relative underperformance of XLY the past couple weeks has caught the attention of some technical analysts as a potential warning sign. [Retail ETFs Hit Record Highs as Consumers Turn Upbeat]

The consumer discretionary ETF was lagging again on Monday, said Investors Intelligence analyst Tarquin Coe in a newsletter.

“This area has been leading the rally and the relative weakness evident is another clue that the overall market is due some oxygen,” he said.

“On the relative chart window, note the test underway of the rising trendline drawn up from late February,” Coe added. “Breaking that line would no doubt coincide with some corrective action on the broader market.”

Consumer Discretionary Select Sector SPDR

The opinions and forecasts expressed herein are solely those of John Spence, and may not actually come to pass. Information on this site should not be used or construed as an offer to sell, a solicitation of an offer to buy, or a recommendation for any product.