When banker Jody Grant and energy mogul Kelcy Warren began exploring plans for Warren’s naming-rights gift to what’s now Klyde Warren Park, the earliest discussions took place at Warren’s island-estate off Honduras, at a meeting of something called Tiger 21.

Both men are members of the Dallas chapter of Tiger 21, a little-known “peer-to-peer learning group” for ultra-high-net-worth individuals. The group discreetly helps the super-rich preserve and grow their money and deal with the problems that often accompany great wealth.

Founded in 1999 by New York real estate entrepreneur Michael Sonnenfeldt, Tiger 21—an acronym for The Investment Group for Enhanced Returns in the 21st Century—has nearly 200 members in 18 chapters around the country.

Members, who are carefully vetted with background and other checks, must have at least $10 million in investable net worth. Preferably, it’s money they made themselves. They pay annual dues of $30,000 and meet once a month to discuss such topics as philanthropy, family dynamics, estate planning, and new investment opportunities.

Periodically they also undergo something called a “portfolio defense,” where members open up their holdings to scrutiny—and suggestions—by the whole group.

“High-net-worth individuals suffer from what I call isolation disease,” says Bill Case, a Plano-based mergers-and-acquisitions specialist who chairs the Dallas club. “They tend to live in good neighborhoods, with big gates and big doors. They sense that everybody’s after them for something, and it’s hard to find peers.

“You can’t share this stuff at your country club,” Case goes on. “Some of the guys in the foursome may not have significant wealth.”

Tiger 21’s Dallas chapter, which was established in 2007 and is still the only outpost in Texas, includes several groups of 12 to 14 members each. Although the membership rolls are not publicly disclosed, Case says, “you would know most all of them.” Most members tend to be “behind the scenes,” he adds, “doing very important things with their resources.”

They represent industries such as insurance, banking, oil and gas, robotics, and private equity, Case says. Some are fifth- or sixth-generation Texans. Monthly meetings last all day behind closed doors at tony spots like the Ritz-Carlton hotel or the Old Parkland campus here, or at a luxury home in Colorado’s Rocky Mountains.

While most Tiger 21 members in Dallas stay under the radar, a few agreed to talk with D CEO for this story. One is Marvin E. Blum, an attorney with an estate-planning practice in Fort Worth. Blum says the membership’s expertise in various fields like medicine, art, and travel has been invaluable to him, as has the group’s investment advice. When he realized during the meetings that he was “overinvested in stocks,” Blum recalls, he diversified his portfolio with real-estate-mortgage instruments.

Another member of the Dallas group, Larry Mueller of Cuvee Ventures, a Denver-based private-equity fund that invests in high-end residences, says he most appreciates Tiger’s “very candid perspective” on financial issues, “without someone trying to sell you something.”

That appreciation is shared by Janet Jensen, another member of the Dallas chapter who made her fortune in private equity. “Money brings you a lot of nice things, but it’s a huge responsibility,” Jensen says. Tiger 21 “is a place where I can go where I feel safe and really express what’s going on, and the other members will give me their best thoughts.”

Proving, it seems, that the 1 percent need TLC, too.