We are skeptical, especially for loans that already exist. A mortgage is a contract, a note secured by a deed of trust, and the rate is a term of that contract. Existing loans cannot simply be rewritten to travel with you, and lenders have zero incentive to let a below-market loan follow you when a payoff would let them relend that money at current levels. Due-on-sale clauses have existed for decades precisely so a below-market loan does not transfer to a new property or a new borrower. Portability is possible in theory. Some other countries allow loans to move with the borrower, so it could exist here for future loans designed that way from the start. What it would almost certainly require in the US is a government-backed structure through Fannie Mae, Freddie Mac, FHA, or VA, or some form of subsidy, rather than a simple rule change applied to loans already on the books. Watch it as a policy idea if you find it interesting. Nobody can promise it happens, so do not plan your next move around it.