The Rainbow Casino is up for sale as its parent company shifts its focus to other businesses, the gambling barge’s manager said Tuesday.

Rainbow General Manager Curt Follmer said the sale is part of a five-year effort by Bally Technologies of Las Vegas to unload assets not related to its main business of manufacturing, distributing and operating gaming devices.

“I knew this day would come, I just didn’t know when,” Follmer said.

If a buyer is found, Rainbow will be the third of Vicksburg’s four original casinos to change ownership.

The casino-hotel complex was listed last week for sale by the global financial-services institution Credit Suisse, whose Los Angeles office is handling the potential deal, Follmer said.

Bally does not plan to sell the casino at a price just “to get rid of it,” Follmer said, adding that no buyer had been identified and he did not know when the casino would sell.

When the Rainbow opened, it was Bally’s first venture into the casino business.

Rainbow initially partnered with Six Flags and had a mini-amusement park on its site with indoor and outdoor rides and attractions as well as its hotel.

It has undergone several renovations, expansions and improvements, including a $1 million project completed at the casino in 2005.

Bally Technologies information says its history dates to 1932 and that it is the world’s No. 1 gaming-systems company. Rainbow is the only casino it owns.

“We are (Bally’s) last noncore asset,” Follmer said.

Casinos were authorized in selected Mississippi counties in 1990 and by referendum in Warren County in 1992. Harrah’s opened Mississippi’s first casino-hotel in November 1994 and was the first local operator to sell. It is now Horizon.

The Isle of Capri was the first casino to open here when it opened in August 1993. In July, that company sold Vicksburg and Bossier City, La., operations to DiamondJacks.

Ameristar, which opened in February 1994, is the largest casino here and commands the largest market share. The company is completing the first of two parking garages and plans a second hotel as part of a $150 million expansion now under way.