What happened

Shares of Tennessean ball bearings maker NN, Inc. (NNBR 3.53%) jumped in early Thursday trading, and were up 14.1% as of 11:30 a.m. EDT.

So what

This being earnings season, you might suspect that an earnings report had something to do with NN's run -- and you'd be right. Yesterday after close of trading, NN reported its fiscal first-quarter numbers.

Sales for Q1 increased 7% year over year, to $226.3 million. Even better, NN reversed its year-ago loss, delivering per-share profits of $0.27 in Q1 2017. "Adjusted," or pro forma profits, were $0.47 per share, which was $0.05 ahead of analyst estimates -- which helps to explain investors' sudden enthusiasm for ball bearings.

Riding a bull market up the stock chart.

Image source: Getty Images.

Now what

NN declined to give guidance for the rest of this year in its earnings report, but here's what the analysts have to say: For full-year 2017, Wall Street thinks NN will book about $858.6 million worth of sales, and earn $1.72 in profits thereon. But because the analysts give their estimates in "pro forma" form, it's hard to work a valuation on such slightly flaky data. Instead, let's look at what NN has done in real, GAAP terms, to date.

Over the past 12 months, NN has produced $0.61 per share in real net profit. The stock currently trades for $30.95 after its run-up, which results in a P/E ratio of more than 50 on the stock, based on actual results. Even with analysts positing a growth rate in the mid-teens over the next five years, that seems to me like a rather high price to pay for stock in a company producing -- let's face it -- essentially a commodity product.

If I were an NN owner today, I think I'd be using today's price spike as a great excuse to cash out.