In her resignation letter, Bass wrote, "Over the past few years, my escalating concerns over serious issues of governance made it impossible for me to continue. I am no longer willing to support an institution that increasingly bears so little resemblance to the one that George Balanchine and Lincoln Kirstein bequeathed their successors...."

According to the Observer, Bass, who was previously married to the Texas investor Sid Bass, has given NYCB more than $5 million over more than two decades. In January of this year, however, she withdrew a $1 million donation to NYCB's School of American Ballet. She resigned on September 30.

In the letter, Bass said that Peter Martins, NYCB's ballet master-in-chief since 1983, unfairly forced out Suzanne Davidson, the former director of NYCB's School of America Ballet, in 2003. This year, she wrote, he expelled an SAB student weeks before his graduation because of "boardroom politics." The student, a Cambodian dancer who was discovered and sponsored by Bass, had allegedly thrown a violent temper tantrum in class.

Martins was not available to comment for the Observer story. Marcia Thompson, a member of the board of SAB, said changes on the board were not unusual. "There are always people coming and going off the board," she said. "There [are] artistic differences as well as administrative differences."