Most U.S. real-estate markets are past the worst of the housing bust, but homeowners—especially boomers—are still citing real-estate scams and mortgage frauds among their biggest complaints to federal regulators.

According to the Federal Trade Commission, real estate and mortgage issues were both in the top 25 categories of complaints for 2011 and 2012. And those in their 50s had the most to complain about, accounting for 23% of all fraud complaints.

Many boomers may be seeking to downsize from large family homes, while others are overextended or upside down in their mortgage.