Britain’s landlords are purchasing fewer buy-to-let homes, worsening a supply shortage that’s causing rents to skyrocket, according to real estate brokerage Hamptons.

Landlords purchased 10% of all homes sold across Britain during the first half of the year, the smallest share since records began in 2010, Hamptons said in a report. That comes even as yields rose to record highs across the country, showing the impact that higher borrowing costs and policy changes are having on the rental-investment market.