Prison companies are preparing for a wave of new business as the economic downturn makes it increasingly difficult for federal and state government officials to build and operate their own jails.

The Federal Bureau of Prisons and several state governments have sent thousands of inmates in recent months to prisons and detention centers run by Corrections Corp. of America , Geo Group Inc. and other private operators, as a crackdown on illegal immigration, a lengthening of mandatory sentences for certain crimes and other factors have overcrowded many government facilities.

Prison-policy experts expect inmate populations in 10 states to have increased by 25% or more between 2006 and 2011, according to a report by the nonprofit Pew Charitable Trusts.

Private prisons housed 7.4% of the country's 1.59 million incarcerated adults in federal and state prisons as of the middle of 2007, up from 1.57 million in 2006, according to the Bureau of Justice Statistics, a crime-data-gathering arm of the U.S. Department of Justice.

Corrections Corp., the largest private-prison operator in the U.S., with 64 facilities, has built two prisons this year and expanded nine facilities, and it plans to finish two more in 2009. The Nashville, Tenn., company put 1,680 new prison beds into service in its third quarter, helping boost net income 14% to $37.9 million. "There is going to be a larger opportunity for us in the future," said Damon Hininger, Corrections Corp.'s president and chief operations officer, in a recent interview.