Caterpillar (CAT:US) reported results for the third quarter that topped analyst views.

Still, shares declined over 5% in New York trading on Tuesday after the engineering equipment manufacturer said on the earnings call that its backlog is decreasing, which suggests that customer demand for its machinery may be weakening. 

The backlog decreased by 8.5% on a quarter-over-quarter basis. Revenue rose 12% to $16.81 billion, just ahead of the consensus of $16.6 billion.

The key business segment – Machinery, Energy & Transportation – generated $15.99 in revenue, up 12% YoY.

“I’d like to thank our global team for delivering another great quarter, as demonstrated by double-digit top-line growth, strong adjusted operating profit margin and robust ME&T free cash flow,” said Chairman and CEO Jim Umpleby. 

“We remain focused on supporting our customers’ success and executing our strategy for long-term profitable growth.”

Adjusted earnings per share were reported at $5.52, easily ahead of the consensus of $4.77.

The decline in CAT stock price comes as Senator Markwayne Mullin reported he was purchasing shares in recent months.

Mr. Mullin bought $15,000 - $50,000 worth of stock on September 13, when it closed at $275.92. 

Shares were trading below $230 apiece on Tuesday.