The iShares Transportation Average ETF (NYSEArca: IYT) and the SPDR S&P Transportation ETF (NYSEArca: XTN) each finished lower last week and some traders are concerned about the signals being sent by transportation stocks.

Going forward, the allure of infrastructure investing, which investors can easily engage in via exchange traded funds, could and should rise as governments around the world finally commit the capital necessary to upgraded dated and dangerous bridges, pipelines and roads. In the near-term, however, transportation investments could remain challenged.

“The last time the DJT was down more than 2% for the week at the same time the DJI was up at least 1% was in late July 2017,” said Schaeffer’s Investment Research. “Prior to that, you’d have to go back to July 2006 for a signal. In fact, it’s interesting to note that the last four signals occurred in the month of July. The year with the most signals was 1998 — during the height of the dot-com boom — with three. Since 1919, there have been just 23 such signals of DJT/DJI divergence, according to data from Schaeffer’s Senior Quantitative Analyst Rocky White.”

IYT tracks the Dow Jones Transportation Average (DJT). Transportation stocks were expected to benefit from lower oil prices and while that has been the case for airline stocks, other industry groups represented in IYT, including railroads, have lagged broader equity benchmarks.

The U.S. Global Jets ETF (NYSEArca: JETS) also stumbled last week, losing nearly 5%.

Showing Page 1 of 2