Industry luminary Sam Zell, chairman of Equity Group Investments, lauded REITs' consistency over the years on the first day of REITWeek2010, held this week in Chicago. The size of the REIT market today is approximately $500 billion. In January 1993, it was $6 billion. "That's an impressive compounded rate of growth," Zell said. Zell added that for REIT investors, a large part of the value comes from having a liquid security. Listen to a replay of the session.