Story highlights Prison companies G4S, CCA respond

Columbia University says it will stop investing in private prison companies

The decision follows a student activist campaign

(CNN) Columbia University has become the first college in the United States to divest from private prison companies, following a student activist campaign.

The decision means the Ivy League school -- which boasts a roughly $9 billion endowment -- will sell its estimated 220,000 shares in G4S, the world's largest private security firm, as well its shares in the Corrections Corporation of America (CCA), the largest private prison company in the United states.

The campaign began in early 2014, when a small group of Columbia students discovered the school was investing in the two firms, which run prisons, detention centers, and militarized borders.

The group, called Columbia Prison Divest, launched protests and meetings with administrators, arguing it was wrong for the elite school to invest in a "racist, violent system."

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"The private prison model is hinged on maximizing incarceration to generate profit -- they're incentivized by convicting, sentencing, and keeping people in prison for longer and longer times," Dunni Oduyemi, a 20-year-old organizer, told CNN.

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