NEW YORK CITY—At this stage, strong fundamentals notwithstanding, “the best years of this property cycle are now behind us, writes Andrew Nelson, chief economist with Colliers International. Among the unmistakable signs: fewer sales and leasing transactions, falling returns, flat capitalization rates and investors chasing yields into secondary markets and riskier assets.

However, Nelson adds, “we're not ready to pronounce an end to this economic expansion, which has been so good to the property sector.” It's been going on for more than 100 months, and by mid-2018 the expansion will be the second longest in US history.

At the same time, though, Nelson notes that “the economy has been mired in a rut of relatively moderate growth for the entirety of this recovery and expansion.” Growth in GDP has averaged just 2.2% per year in this cycle, compared to 3.1% since 1960.