Tesla Motors' (NASDAQ:TSLA) first-ever profit sent its shares soaring to new heights. But a closer look showed something surprising: A big chunk of its revenues came from the sale of tax credits to other automakers.

In this video, Fool.com contributor John Rosevear takes a closer look at Tesla's earnings -- and at whether the tax credit issue should be a concern for investors.

Motley Fool contributor John Rosevear has no position in any stocks mentioned. The Motley Fool recommends Tesla Motors. The Motley Fool owns shares of Tesla Motors. 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.