Tallman has held the position since he stepped in as interim executive director in December 2003, after the departure of Charles Gardenhire.
According to the Denver Post, Tallman and his wife, Angela, who has resigned her position as the company's manager of ticketing and customer relations, are planning to return to a nonprofit consulting business they launched in the late 1990s.
"We've worked for 24/7/365 for the last 18 months," Tallman told the Post, "working hand-in-hand with the trustees and the staff to try and get the ballet ot a much better financial position, which we have done, and now it's somebody else's turn."
Tallman is credited with bringing the company back from a $497,000 deficit, and with increasing donations and overhauling its marketing. Under his leadership, the company decided to buy the Temple Events Center, which will be renovated and turned into a theater, with studios and offices.
The company recently took a new Christopher Wheeldon production off its 2005-06 schedule, saying that it was financially impractical.
Tallman says he leaves "100 percent supportive of the ballet," and willing to serve in some future capacity, such as volunteer, trustee, or consultant.
Lisa Snider, a research analyst and coordinator, has been named interim executive director. She was the company board co-treasurer from 1994 through 1998.