These are wonderful times for commercial real estate investors.

In 2004 alone, prices rose 26% for apartment complexes, 21% for industrial properties, 14% for retail properties and 6% for office buildings, according to Real Capital Analytics, a New York research firm. While prices rose at a slower rate in 2005 and 2006 and 2007, these years marked nine consecutive years of rising prices.

This market gives no sign of slackening even as interest rates have risen over the past several years. While a number of major institutional and private investors have sold off portions of their commercial portfolios, this can be seen as profit taking or diversification, both rational motives.

For each of these sellers there has been a return buyer, as other investors rush forward to buy at record prices. This raises the question of whether the commercial market is as seriously overvalued as portions of the housing market have proven to be. The answer matters not only to individual and institutional investors who are committing ever great sums into the commercial market, but also to the growing number of companies who use property they own to obtain cheap financing.