Two big players in SLOT the leasehold sector have agreed to change the way they operate, following an investigation by the competition watchdog.
Housebuilder Persimmon will allow its leaseholders to buy the freehold of their property at a discount.
Insurance company Aviva, which buys leaseholds from house builders, will repay homeowners who saw their ground rents double.
Campaigners for leaseholders said the commitments were a "massive milestone".
The Competition and Markets Authority (CMA) launched its investigation into leaseholds in 2019 because it was worried that leaseholders were facing huge and unexpected increases in the cost of buying a freehold or massive increases in ground rents.
It said the said the commitments by Persimmon and Aviva were a "real win".
CMA chief executive Andrea Coscelli said the watchdog now expected other housing developers and investors to take similar action.
"This is a real win for thousands of leaseholders - for too long people have found themselves trapped in homes they can struggle to sell or been faced with unexpectedly high prices to buy their freehold.
"But our work isn't done. We now expect other housing developers and investors to follow the lead of Aviva and Persimmon. If not, they can expect to face legal action."