South Florida closed 47 transactions above $10 million in Q4 2024, the highest quarterly count since late 2020, according to Realtor.com market analysis released this week. Total consideration for ultra-luxury closings in Miami-Dade, Broward, and Palm Beach counties exceeded $2.4 billion for the trailing twelve months, a 31% increase year-over-year. The buyers are not tourists.

The acceleration tracks cleanly to migration patterns documented by IRS change-of-address filings: California and New York households relocating to Florida rose 18% in 2023, with the median adjusted gross income of movers exceeding $840,000. Florida's zero state income tax becomes a 13.3% annual dividend for a California seller of a mid-nine-figure business. Waterfront estates in Palm Beach and Miami Beach that sat for 240+ days in 2022 now close in under 90. Sellers are finally pricing to the new bid, and the bid is arriving with Delaware LLCs and 1031 exchange structures already in motion.

This is not a liquidity event. It is reallocation. The $10 million threshold matters because it separates aspirational buyers from those with permanent capital and operational flexibility. These households do not need to be in San Francisco or Manhattan. They need fast commercial flights, offshore banking infrastructure, and a legal domicile that does not penalize liquidity. South Florida now offers all three, along with a time zone that covers both London opens and West Coast closes. The Trump administration's discussion of eliminating the state and local tax deduction cap would, perversely, strengthen Florida's position—high-tax states lose their last federal subsidy, making the migration arithmetic even more compelling for the $5 million+ income cohort.

Palm Beach County led with 22 closings above $10 million, followed by Miami Beach with 14 and Coral Gables with 6. Trophy assets—direct Intracoastal or oceanfront parcels over 15,000 square feet—are now trading at $3,200 per square foot, up from $2,400 in early 2023. Developers are responding: nine new ultra-luxury condo projects broke ground in 2024, targeting delivery in 2027-2028 with presale reserves already 60%+ committed. The supply response will arrive, but it will arrive slowly, and it will arrive at higher replacement cost. Land in Miami Beach is finite. Permitting timelines are not compressing.

Allocators should track California legislative attempts to impose exit taxes on high-net-worth residents, which would accelerate pre-emptive relocations. Watch for Q1 2025 property tax assessments in Palm Beach County—any downward revisions would signal oversupply risk, though none are expected. Monitor mortgage origination data above $5 million: cash transactions currently represent 68% of ultra-luxury closings, but any shift toward financing would indicate either capital constraints or tactical leverage deployment.

The four-year high is structural, not cyclical. California is not fixing its tax code. New York is not repealing its mansion tax. The households that can move, have moved. The households that haven't yet, are now watching their neighbors close on Fisher Island penthouses while their Atherton property taxes climb past $420,000 annually. The delta writes its own headline.