Months of supply is the cleanest single indicator of negotiating leverage, but only when measured at the level you are actually transacting in.
Under three months favors sellers, three to six is balanced, above six favors buyers. Adjacent neighborhoods routinely sit on opposite sides of that line.
We publish this measure monthly for every market we serve, alongside median price per square foot and absorption trend.
From the book
This topic is covered in depth in A Guide to Cooperative Living. A free sample chapter is available.