@Charlie Cameron it allows the person selling to save in taxes on their new home. I'm sure Casey can answer this better than me, however this is my understanding. If the home is homesteaded and the difference between assessed value, market value, and sales price is more than 85k the seller can use that difference as a tax savings in the next home up to $500k. see photo, assessed value $243k market value $355k the tax portability right now is $112k but this home just hit the market at $485k now there is a difference of $130k. the seller can port $242k in tax savings on his new property. Ideally it's used on an upgrade not a downgrade of a purchase. If seller now buys a $650k home the new market vale on that home would be at $420k and assessed lower therefore saving thousands of dollars in property taxes every year. He has 36 mo after the sale to use it on a new home. I hope this helps! Also I'm sure Casey would not mind taking a "vacation" to Destin and explain it in person lol.