There are two aspects: supply and sales activity overall, and the more obscure but highly indicative "preconstruction market."

Preconstruction condos are a favorite playground for condo flippers. They buy the units before construction begins. When the building is completed, some of the buyers (in recent years 30% to 40%) flip their units at a profit, benefiting from the run-up in condo prices in the interim. This activity is crucial in helping developers fund their working capital. Alas, the math has stopped working.

The overall condo and townhouse market in Miami-Dade County is already in trouble. In October, sales plunged 30% year-over-year, while inventory for sale rose to over 14,000 units as of November 1, according to StatFunding's Preconstruction Condo Market Update.