NEW YORK— Since its 1947 founding, the legendary Magnum photography co-op “has never really been in the business of making money,” says its managing director, Mark Lubell. And for much of its history, he says, it “has done a very good job of not making any." But as a result of its recent sale of nearly 200,000 prints by more than 100 photographers — including Henri Cartier-Bresson, Robert Capa, and Rene Burri — to computer billionaire Michael Dell's MSD Capital, Magnum, for the first time in its history, has a big chunk of money to spend. And the public will benefit as well, as the result of the collection's loan to the Ransom Center at the University of Texas, where it will be on display for five years. But a mystery remains: just how much is the Magnum photo trove worth?

No one involved with the sale will say, though the prints have reportedly been insured for $100 million. That insurance figure is likely based on a “blockage discount,” according to Vivian Ebersman, director of art expertise at AXA Art Insurance Corporation. (She did not insure or appraise the collection, but has done so for other large archives.) In other words, “the market value of lots of photographs is less than each one would be individually,” she explains. “The theory is that if all the photos were put on the market at one time, the market would be flooded, so the value would come down.” Equally remarkable is what that $100 million means regarding the value of the images themselves, for which Magnum has keenly retained the rights. These include shots that long ago entered our national image bank, and which are each worth a small fortune due to their fame: Elliot Erwin’s picture of a black man drinking from a water fountain labeled "colored"; Capa’s shots of GIs landing on the beaches of Normandy; Thomas Hoepker’s 1966 portrait of a rather vulnerable-looking Muhammad Ali, right fist extended to the camera.

Lubell, who joined Magnum in 2004 and assumed his post in 2006, came from a background in private equity. He describes his idea to sell the prints as “the 101 of business.” Magnum, he says, was a strong brand but had limited funds, and the changing media landscape — which involved dwindling photo assignments and a diminished licensing business, once Magnum’s traditional revenue streams — spelled “a perfect storm” for the organization. So Lubell looked around the co-op, he says, and asked himself, “What are the opportunities here?”

He found his answer in the organization’s archive, which effectively documents the history of photojournalism, charting the careers of its most-famous practitioners and providing a visual history of the 20th century. Hard to grasp in today’s globalized world, too, but evident in the collection, is the extent that Magnum photographers traveled to shoot their stories; many prints in the archive depict such once hard-to-reach locales as Cuba and Russia, then guarded behind the Iron Curtain. The backs of the prints — marked with stamps, bar codes, and even handwritten notes — furthermore tell the story of the business of photojournalism as it was practiced before digital photography and the Web took over. (The archive ends in 2003; in 2004 Magnum began distributing images digitally.)

After having the archive formally appraised, Lubell developed a three-year “turnaround business plan” to move the co-op away from the revenue streams it had traditionally relied on. Magnum’s 51 members and 13 estates voted for the plan unanimously. The collection’s iconic images are sure to be a major draw. But Ransom Center curator David Coleman points out the value of the collection’s many photos of historically significant events that, for various business or aesthetic reasons at the time, never received much exposure. Seen alongside the iconic images, the lesser-known pictures might function the way that B-side tracks do for musicians, providing a deeper, more rounded understanding of a photographer's work than just the greatest hits. Coleman cites the example of Cartier-Bresson, whom he hadn’t realized had photographed Martin Luther King.