AvalonBay Communities ($138.69 0.67%), the second-largest publicly traded U.S. apartment owner, fell the most in more than a year after forecasting earnings for this year that are below analysts’ expectations.

Funds from operations for 2013 probably will be $4.17 to $4.47 a share, down 19 percent from last year based on the midpoint of the range, the Arlington, Virginia-based real estate investment trust said in a statement yesterday after the close of regular U.S. trading. The average estimateof 18 analysts in a Bloomberg survey is for FFO, a cash-flow measure used by REITs, of $6.20 a share.