Reviews of President Donald Trump’s first 100 days in office are mixed, but there’s no debating this fact: Shares of GEO Group have been on a tear since Trump was inaugurated Jan. 20.

Investors are betting on Trump to make good on his promise of an immigration crackdown. Boca Raton-based GEO Group, a private prison operator that runs detention centers for U.S. Immigration and Customs Enforcement, is poised to house more inmates in a Trump administration.

Shares of GEO Group closed Jan. 19 at $26.03 (adjusted for a recent three-for-two split). On Friday afternoon, GEO Group traded at $33.31, a 28 percent gain that makes the company a stellar performer during Trump’s first 100 days. Atop that impressive return, GEO Group pays a hefty dividend of more than 5 percent a year.

GEO Group isn’t the market’s hottest stock since Jan. 20. Panera Bread Co., to name one rocketing issue, is up 46 percent in that time. But GEO Group has easily outpaced the Standard & Poor’s 500 index, up 5 percent in Trump’s first 100 days.

GEO Group isn’t the only beneficiary of the “Trump trade.” Shares in GEO Group’s main rival, CoreCivic, are up 26 percent since the inauguration.

“The president has come to office promising to deport a lot of people and lock a lot of people up, so of course their stocks are up,” said Paul Wright, director of the Human Rights Defense Center in Lake Worth.

Geo Group executives declined to discuss the stock’s run-up. In a February conference call with Wall Street analysts, GEO Group Chairman and Chief Executive George Zoley said he expects Trump to usher in an “expanded and more aggressive border security program.”

“I believe ICE has been visiting various facilities around the country to expand its capacity because of, among other things, the discontinuation of the catch-and-release program, which meant essentially, as people were caught illegally crossing the border, they were held very temporarily and just let go instead of being detained,” Zoley said. “I think the new policy requires, in most cases, detention and informal processing of the individuals, and that will take several thousands of beds.”

Shareholders of GEO Group have ridden a roller coaster in recent months. On Aug. 18, former President Barack Obama’s Justice Department said it would stop renewing contracts with private prisons, and GEO Group shares shed half their value in just a few hours.

“Private prisons served an important role during a difficult period, but time has shown that they compare poorly to our own [federal] facilities,” a deputy attorney general wrote at the time. “They simply do not provide the same level of correctional services, programs, and resources; they do not save substantially on costs; and as noted in a recent report by the Department’ s Office of lnspector General, they do not maintain the same level of safety and security.”

GEO Group stock recovered some of those losses during the summer, but with most investors expecting Hilary Clinton to beat Trump, the company’s shares languished. Then, on Nov. 9, the day after Trump’s surprise victory, GEO shares soared more than 20 percent.

“We won’t speculate about future policy initiatives,” GEO Group said in a statement, “but we look forward to working with both the new administration and the new Congress in continuing our longstanding partnership with the federal government providing high-quality and cost-effective services, while treating those entrusted to our care with the respect and dignity they deserve.”

GEO Group’s share price has proven far more volatile than the company’s underlying business of hiring guards and holding inmates under contracts with federal and state agencies.

Revenues have grown steadily, climbing gradually from $1.48 billion in 2012 to $2.18 billion in 2016. GEO Group is solidly profitable, although profit margins have been smaller in recent years.

Socially responsible investors recoil at such a play: GEO Group has been cited time and again by federal and state regulators for horrid conditions at its facilities, concerns that led Obama’s Justice Department to announce fewer deals with GEO Group and other private operators.

In one example, Texas in 2007 canceled an $8 million contract with GEO Group and closed the Coke County Juvenile Justice Center. Inspectors found feces on floors, padlocked emergency exits and overuse of pepper spray on young inmates.

However, Trump has said he believes private prisons can operate more efficiently than government-run prisons.

“That’s the lie they’ve perpetuated,” Wright said. “Can they run a prison cheaper? Sure they can. But all their savings come from cutting staffing.”

In fact, wages are just one place where GEO Group can skimp. In a 2008 report, the Florida Office of Program Policy Analysis & Government Accountability looked at the state’s private prisons and concluded that operators save money by taking on fewer “special needs” prisoners with medical problems and mental health issues that make them expensive to house.

Such findings have led critics to question the wisdom of outsourcing prisons to for-profit companies.

“It’s literally all a political decision,” Wright said. “It has nothing to do with how good or bad their services are or the value they provide.”