The widening underperformance between the industrials sector and related industrial ETFs to the rest of the S&P 500 could signal further market troubles ahead.

The Industrial Select Sector SPDR (NYSEArca: XLI), the largest ETF tracking industrial stocks, declined 5.0% over the past month while the S&P 500 gained 0.8%. Year-to-date, XLI fell 3.6%, compared to the 3.1% rise in the S&P 500.

Matt Maley, an equity strategist at Miller and Tabak & Co., pointed out that XLI historically has been “ridiculously, highly correlated” to the moves of the broader market, reports Olivia Schaber for Bloomberg.

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