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 ReneSola Ltd. (NYSE:SOL) sank 6% today after Roth Capital downgraded the solar products specialist from buy to neutral.

So what: Along with the downgrade, analyst Philip Shen lowered his price target to $2.75 (from $5), exactly where the stock closed yesterday. So while contrarian traders might be attracted to ReneSola's sharp year-to-date price sluggishness, Shen's call could reflect a sense on Wall Street that its near-term headwinds are just too strong to allow for a significant rebound.

Now what: Roth expects ReneSola's profitability and cash flow to erode over the next couple of years. "While we acknowledge module ASPs are often more attractive in the DG segment, winning large volume orders can be difficult," said Shen. "This could create headwinds to module shipments and topline growth. Moreover, building out the necessary sales and distribution network to stay close to end customers will likely result in increased opex." Of course, with ReneSola shares now off about 55% from their 52-week highs and trading at a single-digit forward P/E, much of that risk might already be baked into the valuation. 

Brian Pacampara has no position in any stocks mentioned. The Motley Fool has no position in any of the 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.