A handful of American businesses have their fingers in almost every aspect of prison life, raking in billions of dollars every year for products and services — often with little oversight.

The big picture: Taxpayers, incarcerated people and their families spend around $85 billion a year on public and private correction facilities, bail and prison services, according to the Prison Policy Initiative.

For-profit prison companies arose in response to the government's incapacity to handle the skyrocketing incarcerated population.

Now entrenched, they've become "one more hurdle" to changing the American system of mass incarceration, Lauren-Brooke Eisen of the Brennan Center for Justice told Axios.

These companies also have been known to cut corners — sometimes endangering people — in order to profit off of a system that disproportionately impacts the impoverished and marginalized.

Here's how they make money:

📞 Phone calls

About 80% of inmate calls go through Securus or GTL, both owned by private equity and known for sometimes charging outrageous fees ($8.20 for the first minute, in one case cited in a lawsuit).

People in prison also can be charged extra to open and close phone accounts, plus a surcharge to fund them in the first place.

🚑 Medical services

The largest private provider of medical services to prisons is believed to be Corizon Health, operating in 220 facilities in 17 states and owned by a New York City hedge fund.

Pricing: Corizon was paid $15.16 per incarcerated person per day for medical staffing in Arizona's prisons, before being accused of cheating state monitors and losing the account to another private company.

🍔 Food services

Two companies — Aramark and Trinity Services — provide meals in around 800 state and local facilities.

The Michigan Department of Corrections awarded a $145 million contract to Aramark, then fired the company for everything from "meal shortages to maggots in the kitchen," and replaced the company with Trinity at an annual cost of $158 million.

Problems persisted under Trinity, causing Michigan to abandon privatized food services in its kitchens.

🚗 Transportation services

Tennessee-based Prisoner Transportation Services is the largest provider of transportation for jails and prisons.

In 2016, PTS priced its services to Nevada at $1.05 per adult per mile, with higher rates for minors or those with mental disabilities. The minimum trip fee was $350.

In the past several years, 14 women claimed to have been sexually assaulted by transportation guards and at least 4 people have died while being transported in PTS vehicles, per the Marshall Project.

👕 Clothes, toiletries, etc.

Incarcerated people and their families spend an estimated $1.6 billion every year on commissary items such as toiletries, clothes and games.

While these items aren't generally marked-up, people in prison make very little money to afford what they need.

Keefe Group and Bob Barker Company are two companies that specialize in producing secure items as well as supplying cell furniture, guard equipment and supplies.

What’s next: With bipartisan attention focused on fighting high recidivism rates, for-profit prison companies are expanding their businesses beyond prison walls.

They’re running re-entry programs intended to prepare people in prison for life after prison, providing ankle bracelets and other monitoring devices for parole and probation, and operating immigrant detention spaces.

A spokesperson for CoreCivic — one of the largest for-profit prison companies — told Axios one of the few areas they lobby for is re-entry programs at the state and federal level.

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