Shares of AvalonBay , which reported an increase in expenses due to higher-than-expected tenant bad debt , eked out a 0.6 percent gain on a day when the REIT sector rose 4.7 percent , according to the benchmark MSCI U.S. REIT Index .RMZ. Equity Residential , whose founder and chairman is real estate mogul Sam Zell , said its deteriorating markets are all in the western United States -- Los Angeles , Orange County , San Francisco , Seattle and Phoenix .