Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of printed circuit board manufacturer TTM Technologies (NASDAQ:TTMI) were up 7.8% at 3:53 p.m. ET on Tuesday on the publication of a research note from JPMorgan Chase upgrading the stock to "overweight" from "neutral." JPMorgan's price target for the stock remains unchanged at $11.

So what: In justifying the upgrade, JPMorgan wrote:

We are upgrading TTMI to Overweight from Neutral based on valuation. 4Q guidance, issued last week, was a bit disappointing, causing the stock to trade down 15% over the last five trading days (S&P500 up 0.22%). We think this yields an entry point for long-term investors. We still anticipate improved demand in 2014 and significantly better margins owing to restructuring action taken in 2013.

Certainly, TTM Technologies' valuation looks attractive on first pass: Based on Monday's closing price, the stock is valued at just 11.6 times the estimate of the next 12 months' earnings per share. However, margin improvement is critical, as the company's EBIT (earnings before interest and taxes) margin was just 4.1% over the 12-month period to Sept. 30.

Now what: I agree with JPMorgan's analysis: Long-term investors may consider that the current price offers a decent entry point for the stock -- provided they can get comfortable with the odds for improved profitability at TTM Technologies. However, I'd remind investors that this company operates in a brutally competitive industry with high capital expenditure requirements. Those characteristics rarely go along with outstanding long-term investments; as such, investors may want to focus on companies with superior economics instead.