Private prisons in the US are rubbing their hands with glee as US President Donald Trump has enacted measures that greatly benefit their bottom line.

The corporations, which pledged hundreds of thousands of dollars to pro-Trump campaigns, are starting to see returns on their investments within months of Trump's inauguration.

On Tuesday, the Department for Homeland Security (DHS) issued two memos that paved the way for detaining millions of illegal immigrants and cracking down on security at the US-Mexico border.

Both memos greatly benefit the private prison industry, which will see their prison populations inflate as the measures are enforced.

GEO Group, one of the world's biggest prison corporations, is among those to have welcomed the changes.

Quoted by The Intercept, the company's CEO George Zoley said in an investor call on Wednesday (22 February): "With the respect to detention services, in support of border security, we would continue to be the largest provider of detention services to the three largest government agencies – that is ICE [Immigration and Customs Enforcement], the Bureau of Prisons, and the US Marshals Service.

"With this increased and expanded approach to border security the first agency that will need additional capacity is ICE."

In another investor call earlier this month, prison company CoreCivic sounded out a similar sentiment.

Damon Hininger, the company's CEO, said: "When coupled with the above average rate of crossings along the southwest border, these executive orders appear likely to significantly increase the need for safe, humane, and appropriate detention bed capacity that we have available," thus increasing the company's profits.

Peter Altabef, the chief executive of Unisys Corporation, which runs IT systems for border security, said: "In general, we feel bullish that our focus is increasingly the focus of the new administration.

"So clearly on things such as border security, which is our largest client in the federal government, I would say we've become increasingly bullish about that."

A Reuters analysis earlier this week (21 February) showed CoreCivic shares are up 138% since 8 November 2016, whereas GEO Group's shares have gone up by 89%.