Investment from Koch gives strength to Guardian

Nearly four years after the death of majority owner Bill Davidson, Auburn Hills-based Guardian Industries Corp. is part of a new family -- the Koch family, led by conservative political activists and industrialists David and Charles Koch.

On Dec. 19, KGCI LLC, a subsidiary of Wichita, Kan.-based Koch Industries Inc., became the largest individual shareholder of Guardian, likely reducing the stakes of longtime Guardian executives and Davidson family members as the company enters a new era of leadership.

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