BOISE, Idaho —President-elect Donald Trump’s promise to deport millions of immigrants in the country illegally and his selection of tough-on-crime Alabama Sen. Jeff Sessions as attorney general could mean big money for the private prison industry.

Some analysts believe the prison population could climb under the Trump administration, and the stock market seems to agree.

A day after the election, CoreCivic Co., formerly Corrections Corporation of America, saw the biggest percentage gain on the New York Stock Exchange with shares climbing 43 percent.

Geo Group, another private prison company, saw its shares jump 21 percent.

The federal prison population had been trending down for nearly a decade when the Obama administration announced in August that it would phase out its use of some private facilities.