MIT has released its most recent data on commercial real estate transactions. Below is its transaction-based index.
Results for the 2nd quarter of 2008 show a 2.7% decline in the capital return for the properties sold in the NCREIF database. The demand-side index continued to fall, by 2.7 percent and the supply side of the market also decreased its reservation prices by 2.8 percent in the second quarter.
Please note that the TBI is a statistical methodology that produces estimates of price movements and total returns based on transactions of properties sold from the NCREIF Index database.
And here is its look at retail prices.