It may have been the last Major League Soccer game for David Beckham, a global brand that continues to be a cash cow off the field, even as his skills diminish off the field.

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"Up until now, patent donations have been a cash cow because the IRS turned an inadvertent blind eye, " says David Martin , chief executive of M-CAM , the Virginia-based company the IRS hired to help detect abusive tax strategies relating to patents.

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