WHEN ADNAN SABIC began looking for a home in 2023, he was shocked. The hotel executive, whose wife had just given birth to twins, could not believe how mortgage rates had rocketed. Then he found a four-bedroom house listed for $775,000 with a nice selling point. Rather than borrow at 6% and pay $4,500 a month, Mr Sabic could “assume” the seller’s mortgage, at 2.6%, and pay just $3,100.