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 Time Warner Inc (NYSE:TWX.DL) gained slightly this morning after Jefferies initiated coverage on the media giant with a buy rating.

So what: Along with the bullish call, analyst John Janedis planted a price target of $80 on the stock, representing about 16% worth of upside to Wednesday's close. So while momentum traders might be turned off by Time Warner's price strength over the past year, Janedis' call could reflect a sense on Wall Street that its long-term growth prospects still aren't fully baked into the valuation.

Now what: Jefferies expects Time Warner's earnings to grow at a compounded rate of 12% over the next two years. "With the publishing spin finally complete, we view Time Warner as a content machine without the issues associated with owning a TV network,"Janedis said. "Moreover, having effectively de-risked the affiliate fee story by providing guidance through '18, and with a secular tailwind of demand for Warner Bros. TV studio content, a compelling return of capital/leverage outlook, and improving ratings leading to peer-like ad growth, should allow the shares to outperform." When you couple that upbeat outlook with Time Warner's still-reasonable forward P/E of 15, it's easy to understand Jefferies' bullishness. 

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.