NASHVILLE (AP) — Corrections Corp of America, the nation's largest prison management contractor, said Thursday that its first quarter net income fell 21 percent due to debt refinancing and other costs, and the company said it was considering converting into a real estate investment trust.

The company also lowered its 2012 forecast. Its shares fell nearly 5 percent in midday trading.

Net income fell to $31.7 million, or 32 cents per share. That compares with net income of $40.3 million, or 37 cents per share, last year. Excluding one-time times related to debt refinancing, net income totaled 33 cents per share, matching analyst expectations, according to FactSet.

Revenue rose 2 percent to $435.3 million from $425.1 million last year. Analysts expected revenue of $431 million.

Management revenue from federal contracts rose nearly 4 percent to $189.3 million, due to higher inmate populations and contractual rate increases for some contracts. Revenue from state contracts rose nearly 1 percent to $215.8 million. Higher inmate populations in Ohio due to a newly acquired prison was offset by the company's decision in 2011 not to renew the contract for 900 beds at a facility in Florence. There the company replaced state inmates with those from the U.S. Marshals Service.

The company also had lower inmate populations in Washington, D.C., and Colorado.

Corrections Corp of America expects second-quarter net income between 36 and 37 cents per share. Analysts expect net income of 41 cents per share.

The company now expects full-year net income to be $1.53 to $1.61 per share, down from a previous estimate of $1.60 to $1.70 per share.

The lower guidance is due to a decline in U.S. Marshals populations, which began late in the fourth quarter and have not rebounded as expected, lower inmate population in Georgia and higher insurance claims.

The earnings came as the company said it is considering converting to a real estate investment trust. That structure would allow Corrections Corp. to own its own prisons rather than just managing them.

Shares fell $1.36, or 4.7 percent, to $27.65 during midday trading. The stock is up 42 percent since the beginning of the year.