In September 2003, the CEO of General Electric must evaluate a final proposal for it to acquire Amersham plc, the leading producer of contrast agents used in medical diagnostics. The case permits the valuation of Amersham based on peer firms, comparable transactions, and recent trading history. But the focus of analysis is on the robustness of Amersham’s intellectual property (IP), which on examination is weaker than it first appeared, given recent patents filed by competitors. In September 2003, Jeffrey Immelt, CEO of General Electric, must evaluate a final proposal for GE to acquire Amersham plc, the leading producer of contrast agents used in medical diagnostics. The case permits the valuation of Amersham based on peer firms, comparable transactions, and recent trading history. But the focus of analysis is on the robustness of Amersham’s intellectual property (IP). On close examination, the company’s IP position is weaker than it appears, given recent patents filed by competitors. The economic impact of these IP challenges may be tested in the case of the company’s leading product, Visipaque, for which the case gives cash flows. Discounted cash flow analysis reveals great sensitivity to the remaining years of effective patent life. A key lesson underscores the importance of due-diligence research on a firm’s IP position.