The National Association of Home Builders' monthly housing market index fell to a reading of 32 in September from 35 in August, compared with expectations for a smaller decrease to 34 in a survey compiled by Bloomberg as of 6:00 am ET.
The index was unchanged from a year earlier.
The readings for single-family sales and the six-month outlook decreased, while the buyer traffic reading remained the same as in the previous month.
"Buyer traffic has weakened across much of the country, largely because of rising mortgage rates," NAHB Chairman Bill Owens said, adding that builders face several challenges including an increase in material costs, higher gasoline prices and continuous labor shortages.
"The HMI shows builder confidence at its lowest level since September 2025, as tight lending conditions and elevated land, labor and construction costs persist," NAHB Chief Economist Robert Dietz said.