The Atlanta Opera, one of the metro arts groups hardest hit by the struggling economy, is receiving a $9 million bequest from longtime board member Barbara D. Stewart, who died last year, the company announced Thursday.

The bequest is believed to be the largest gift in the opera’s history and one of the larger gifts known to a North American opera company.

Greg Johnson, chairman of the opera's board, called the gift "transformative" and said it means the company "is here to stay."

"There is no doubt that this gift will serve as a catalyst for all fundraising efforts going forward," Johnson said in a prepared statement. "This bequest is a phenomenal example of how one individual can make an enormous impact on an arts organization and on the community."

The 31-year-old company, operating under an annual budget of $5 million, knew that Stewart had left something for it in her will, but it didn't know the particulars until it received an attorney's letter Thursday.

"She never gave me dollar amounts," opera general director Dennis Hanthorn recalled. "Instead it was, ‘You're in for a certain percent.' I didn't know what that meant. [Percent] of what?"

Stewart, who beginning in the mid-1990s had served as president, vice president and treasurer of the opera's board, was the founder of Stewart Economics Inc., a consulting firm that specialized in the insurance business.

At Stewart’s request, half the bequest will be used to build the opera’s endowment, raising that fund to $5.6 million. Hanthorn said she told him she hoped that would serve as an incentive to other potential donors to contribute to the endowment. Interest from it will fund one production per year, he said.

The opera will dedicate George Gershwin’s "Porgy and Bess," which opens Feb. 26 at Cobb Energy Performing Arts Centre, to Stewart's memory.

"Sustainability is the key word," Hanthorn said. "I can sleep better at night."

It's a far different tune than the opera leader sang in late January, when the company announced a truncated three-opera schedule for the 2011-12 season.

"If we have one mistake, it's over," Hanthorn told The Atlanta Journal-Constitution while lamenting sluggish ticket sales this season and diminishing cash reserves. "That's how close we are."