Shares of Caterpillar (NYSE:CAT) have hugely underperformed the broader market over the past couple of years, leaving investors in the lurch. An upward revision of its full-year profit guidance, backed by an earnings beat during the first quarter, came as a pleasant surprise, but it was far from indicating a turnaround. Each of Caterpillar's businesses -- resource industries, construction industries, and energy and transportation – continue to face huge challenges.

In fact, things could be turning from bad to worse in some areas for the company, which is terrible news for investors. To know more, check out the following slideshow, where I've highlighted three major factors that could send Caterpillar shares lower.