Don’t expect the Dow Jones Industrial Average’s momentum to 40,000 to stay in place, if one of the oldest indicators on Wall Street is to be believed. The Dow hit an intraday high of 40,051.05 on Thursday before closing slightly lower. It marked the first time the 30-stock average broke above 40,000. However, as R.J. O’Brien’s Tom Fitzpatrick points out, Dow theory signals this run may be short-lived. Dow theory examines the relationship between the industrial and transportation benchmarks named after Charles Dow. It dictates that major market trends must be confirmed by both the Dow Industrials and Transports. Put another way, if the Dow Industrials are rising, then Transports should also be going higher to signal a prolonged positive run. Right now, that is not the case. “The transports are the actual engine of the economy,” Fitzpatrick, the firm’s managing director for global market insights, told CNBC. “We’re at that point again where we’re not getting confirmation from the transports that the activity that’s happening actually supports the fact we’ve hit a new high on the Dow.” While the Dow Industrials reached a fresh record high, Transports have not been as fortunate. Dow Transports in April suffered their worst month since September 2022, losing 8%. The benchmark has not made a fresh record since Nov. 2, 2021, when it reached 18,246.51 on an intraday basis. In 2024, the Transportation index has slipped nearly 2%, while the 30-stock Dow has climbed 7% as of Friday. The Dow Transports index contains components such as airline companies Southwest and United , as well as shipping firm FedEx , which is why the average is a better gauge of activity, Fitzpatrick noted. He also pointed to a confluence of worrying data points, including recent ISM manufacturing , homebuilding and inflation metrics as causes for concern for the overall market. While the latest consumer price index report showed price pressures increased less than expected in April, rent and insurance costs remain sticky and concerning, he added. “We’re clearly increasingly [and] consistently all of a sudden missing in terms of economic data and I think that’s a warning sign,” Fitzpatrick said. What’s more, the actual 40,000 level is more symbolic than meaningful, he said. “Once you get to round numbers, people tend to look at that as ‘a level’ more so than it actually is a level,” Fitzpatrick said. “It’s more psychology than anything else.” The Dow Industrials also have a history of pulling back after a 1,000-point increase .