While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of IMAX (NYSE:IMAX) sank 5% today after Benchmark initiated coverage on the jumbo-movie-screen technologist with a hold rating.

So what: Along with the call, analyst Mike Hickey planted a price target of $29.42 on the stock -- pretty much exactly where it closed on Tuesday -- suggesting that he sees limited upside at current levels. While Hickey is still positive on IMAX's near-term global growth prospects, he thinks that investors might not be baking enough long-term performance risk into the valuation.

Now what: Based on sluggish box office numbers lately, Benchmark thinks that IMAX's third- and fourth-quarter results could disappoint Wall Street. "We remain optimistic near term over the IMAX brand and premium ticket experience they offer to a rapidly unfolding international growth opportunity," Benchmark noted. "We remain cautious over the Company's ongoing performance risk, particularly over a network growth scenario that appears to have slowed meaningfully." With the stock still up more than 40% from its 52-week lows and trading at P/E of nearly 50, I'd agree with Benchmark and wait for a wider margin of safety before jumping in. 

Fool contributor Brian Pacampara has no position in any stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.