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

What: Shares of Alliance Data Systems (NYSE:ADS) gained 2% today after Nomura Securities upgraded the marketing company from neutral to buy.

So what: Along with the upgrade, analyst Tulu Yunus planted a price target of $300 on the stock, representing about 17% worth of upside to Friday's close. So while momentum traders might be turned off by Alliance's price weakness in recent months, Yunus' call could reflect a sense on Wall Street that the company's growth prospects are becoming too cheap to pass up.

Now what: Nomura raised its 2014 earnings-per-share view for Alliance from $12.32 to $12.63 and its 2015 outlook from $14.24 to $14.78. "It's certainly not new news that ADS's PL portfolio continues to grow at a rapid pace," said Yunus. "That said, our analysis of the pipeline suggests that the file's growth will reaccelerate and reach new highs in the 30%+ range later this year. We expect shares to rival their 52-wk high as estimates ratchet higher yet again." Given Alliance's still-hefty debt load and 30-plus P/E, however, I'd hold out for a wider margin of safety before betting on it. 

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.