By Caroline Valetkevitch

NEW YORK, Nov 7 (Reuters) - Shares of prison operators Geo Group GEO.N and CoreCivic Inc. CXW.N surged on Thursday, extending sharp gains following the U.S. presidential victory by Republican Donald Trump, whose promise of tough immigration measures is seen as potentially boosting demand for detention centers.

CoreCivic late on Wednesday reported quarterly results that topped analysts' expectations and raised its outlook. Its stock was last up about 23% and hit its highest level intraday since June 2019.

Geo Group's stock also rose on Thursday despite the company's earlier in the day posting revenue results that missed consensus expectations and lowering its full-year earnings forecast. The stock was last up about 10% and hit its highest level since 2018.

On Wednesday, Geo Group's stock surged 42% and CoreCivic jumped 29% after former U.S. president Trump, who has promised to crack down on illegal immigration, won the White House vote on Tuesday against Kamala Harris, the Democratic vice president.

"Shares moved significantly higher yesterday following the initial results of the election," Wedbush analysts wrote in a note on Thursday.

But, they added, "It is likely too early to fully gauge the impact of election" for either company's outlook.

CoreCivic's chief executive, Damon Hininger, in the company's release said that occupancy rose to 75.2% from 72% in the year-ago quarter and noted an improvement in the operating margin due to expense management and demand for essential services.

CoreCivic's stock is now up about 58% since Tuesday's close, and Geo Group's stock is up about 57% for that period.

(Reporting by Caroline Valetkevitch; additional reporting by Lance Tupper; Editing by Leslie Adler)

((caroline.valetkevitch@thomsonreuters.com))