There are signs that the U.S. housing market is starting to cool down, but there’s still significant overheating in some of the country’s major markets.

UBS analyzed 20 developed cities around the world to assess which are at the greatest risk of a housing bubble. While none of the major U.S. cities are in dangerous territory, San Francisco, Los Angeles and New York are overvalued. Boston is fairly valued while Chicago is the only undervalued city on the list.

The city most at risk of a bubble is Hong Kong, followed by Munich, Toronto, Vancouver and Amsterdam. Being in “bubble territory” refers to a substantial and sustained mis-pricing of an asset, the existence of which cannot be proved unless it bursts, according to UBS.

The Global Real Estate Bubble index scores for the U.S. cities are below their pre-recession 2006 values. There are significant disparities across the cities, with the U.S.’s West Coast overheating at a more rapid pace than the rest of the country.

Home prices in San Francisco, specifically, rose 9% since the summer of 2017 and 80% over the past six years. According to the report, real home prices “now exceed their 2006 peak by more than 20%, amid a thriving local economy, significant non-cash earnings by many tech employees, and buoyant foreign demand.”

But it’s erroneous to compare the 2006 peak prices to today’s landscape, according to Mark Haefele, chief investment officer at UBS Global Wealth Management. The rising home prices are just a sign for investors and homebuyers to proceed with caution.

Melody Hahm is a senior writer at Yahoo Finance, covering entrepreneurship, technology and real estate. Follow her on Twitter @melodyhahm.

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