As the country’s immigration agency ponders a significant expansion of its vast, troubled immigrant surveillance regime, private prison companies are telling investors that the proposal could bring significant profits — and are deploying lobbyists to fight to fund it.

In separate calls with investors last month, executives with two of the world’s largest private prison companies, the GEO Group and CoreCivic, said they were focused on a new proposal to radically expand an Immigration and Customs Enforcement (ICE) surveillance program. According to the plan, the program, which currently keeps tabs on nearly 200,000 immigrants using technologies like ankle bracelets and facial-recognition apps, could eventually track millions of people who are caught in the immigration system.

ICE’s surveillance programs have been a focus of the companies’ multimillion-dollar lobbying efforts in Washington this year, the latest example of how private incentives are shaping ICE’s vast, and growing, surveillance regime.