Pharmaceutical spin-off AbbVie recently received a big upgrade from Wall Street bank Morgan Stanley, sending shares up 6% last week. In this video, health-care analyst David Williamson breaks down what investors need to know about this bullish report, and why they might want to show caution before buying AbbVie stock.

David Williamson owns shares of Pfizer. Follow David on Twitter: @MotleyDavid.

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