That revenue in the Express segment, which is FedEx's largest business, fell by 0.3% serves as a perfect example. As has been the case over the past couple of quarters, management continues to improve efficiency within the Express segment, which can be seen in better profitability, including a 50-basis-point improvement in operating margins this quarter. Oddly, even when there is good news, it comes with some concerns. Take, for instance, the company's strong Ground business, which posted a solid 11% year-over-year revenue increase. While the operating income for that business grew by 5%, operating margins still fell by 100 basis points. Essentially, there was some inefficiency even in FedEx's best performing business. UPS) and Old Dominion ( ODFL), while they're dealing with similar operational issues, are both resting at near 52-week highs. For that matter, it seems the entire transportation sector, which includes Genesee & Wyoming ( GWR), are all "on the move." This group has had an incredible run, but I just don't believe that it can continue for much longer, especially with shipping volumes on a perpetual decline. In the case of FedEx, it's tough for me to ignore the cautious tenor of the company's own management. While it's also possible that management just wants to lower expectations to not set the company up to fail, I can't entirely discount that it could be telling the truth. Given that the stock has -- in my view - risen significantly above the company's performance, it's best to err on the side of caution here. At the time of publication, the author held no position in any of the stocks mentioned. Follow @saintssense This article was written by an independent contributor, separate from TheStreet's regular news coverage.