Several industries have become notorious for the millions they spend on influencing legislation and getting friendly candidates into office: Big Oil, Big Pharma and the gun lobby among them. But one has managed to quickly build influence with comparatively little scrutiny: Private prisons. The two largest for-profit prison companies in the United States – GEO and Corrections Corporation of America – and their associates have funneled more than $10 million to candidates since 1989 and have spent nearly $25 million on lobbying efforts. Meanwhile, these private companies have seen their revenue and market share soar. They now rake in a combined $3.3 billion in annual revenue and the private federal prison population more than doubled between 2000 and 2010, according to a report by the Justice Policy Institute. Private companies house nearly half of the nation’s immigrant detainees, compared to about 25 percent a decade ago, a Huffington Post report found. In total, there are now about 130 private prisons in the country with about 157,000 beds.