Guest Appraiser Columnist:
John Cicero, MAI, CRE, FRICS 
John provides commentary on issues affecting real estate appraisers, with specific focus on commercial valuation. He is a partner of mine in our commercial real estate valuation concern Miller Cicero, LLC  and he is, depending on what day of the week it is, one of the smartest guys I know.
Bob Knakal, Chairman of investment sales brokerage firm, Massey Knakal Realty Services , recently released an excellent commentary on a 25-year history of the New York City multifamily market . Using actual sales data from 1984 to the present (including cap rate data from 2005 to 2008 compiled by my firm, Miller Cicero, LLC).
In addition to examining historical cap rates and gross rent multipliers over time, the report analyzes cap rates relative to mortgage rates and the yields on 10-year T-bills. An excerpt:
From 1994 through 1999, we saw slow steady declines in cap rates, with slightly positive leverage and risk premiums within a range of 100 to 250 basis points…Throughout the 25 years of this analysis, this period was the most stable-and I attribute this stability directly to the very disciplined lending practices of debt providers.
It’s actually fascinating (at least for a commercial appraisal nerd like me!) to see how many NYC multifamily property was routinely purchased with negative leverage (i.e. at cap rates below mortgage rates. In fact the past five years has been the biggest period of negative leverage buying since the mid 1980’s. However, with the more stringent underwriting now in place, the NYC multifamily market seems poised for another (surprisingly rare) period of positive leverage.