Home sales based on contract signings have continued to decline for the second straight month – a sign that the red-hot housing market could be cooling off, according to the National Association of Realtors.

NAR’s Pending Home Sales Index (PHSI), released Monday, showed a 1.8% month-over-month drop in July to a reading of 110.7. Year over year, the index was down by 8.5%.

“The market may be starting to cool slightly, but at the moment, there is not enough supply to match the demand from would-be buyers,” said NAR chief economist Lawrence Yun. “That said, inventory is slowly increasing, and home shoppers should begin to see more options in the coming months.”