Over the last year, Caterpillar's shares have bulldozed their way to new records. Yet that sudden and steep rally has at least one market watcher questioning its sturdiness.

"The stock has had a great run but it's kind of gone vertical in the last two months," said Matt Maley, equity strategist at Miller Tabak, on CNBC's "Trading Nation" on Wednesday. "This is out-of-control overbought."

Caterpillar's relative strength index (RSI) reached the 93 mark this week, overtaking the S&P 500 Index's 88 level. The measure, which tracks the speed and scale of gains in a stock, suggests Caterpillar shares are in overbought conditions.

The construction company's price-to-earnings (PE) ratio is also well above that of its peers. Its 12-month PE sits at 118 times trailing earnings, while competitor Deere & Co. has a PE of 25 and the nearly 23.

When it reports before the opening of Wall Street's bell on Thursday, Caterpillar earnings are expected to rise over the fourth quarter that ended in December, thanks to a stronger economy in the back-half of last year. Adjusted earnings are forecast to more than double to $1.77 a share, while sales should rise by 23 percent.